Fix many doxygen warnings (due to missing info, old comments, typo ...) when building the doxygen doc.

  steps to better support devices with precise scrolling deltas (trackpads).
  Scrolling is done in the handler rather than creating and firing cmd events.
  This is intended to support two-finger scrolling on the Magic Trackpad.
- Added a preference, 'Use mousewheel to pan', to allow panning by default
  on mousewheel events.  This reverses the existing behavior where unmodified 
  mousewheel zooms and Shift/Cmd modified pans.  

  The old behavior was:
  - Unmodified scrollwheel performed zoom in/out
  - Shift modified scrollwheel performed pan up/down
  - Cmd modified scrollwheel performed pan left/right
  - Shift+Cmd modified scrollwheel performed zoom in/out
    with no cursor warp

  With the new preference checked, this changes to:

  - Unmodified scrollwheel performs pan up/down
  - Shift modified scrollwheel performs pan left/right
  - Cmd modified scrollwheel performs zoom in/out
  - Shift+Cmd modified scrollwheel performs zoom in/out
    with no cursor warp

  With the preference unchecked, this is now:
  - Unmodified scrollwheel performed zoom in/out
  - Shift modified scrollwheel performed pan left/right
  - Cmd modified scrollwheel performed pan up/down
  - Shift+Cmd modified scrollwheel performed zoom in/out
    with no cursor warp

  It should be noted that for the last case, the behavior has changed.
  This is not arbitrary.  This now matches expected behavior for an OS X
  application.  This also matches what wxWidgets expects on this platform
  as wxWidgets changes the axis of mousewheel events to horizontal when
  the event is shift-modified.

  The preference is added everwhere that mouse preferences previously
  existed, i.e., eeschema, pcbnew and gerbview.  The 3D Viewer does
  not yet honor this preference, but behaves as if it was checked.
  The pl_editor does not currently have any preferences to honor.

  As with the magnify event support, this covers canvases for all
  current tools, EDA_DRAW_PANEL, EDA_3D_CANVAS and EDA_DRAW_PANEL_GAL.

  This does NOT modify the behavior of mousewheel zooming, though it
  probably should.  This remains unsuitable for use with a trackpad,
  use pinch-to-zoom instead.

Eeschema, Plot dialog: add Plot directory selection. The patch from 1383026@bugs.launchpad.net was widely used.

eeschema: fix Bug #1385789 (eeschema segfaults, when editing a new field). Fix an other minor bug in Footprint editor.

Add FILE_NAME_WITH_PATH_CHAR_VALIDATOR, a custom wxValidator which allows file names with paths, in schematic sheet editor
( FILE_NAME_CHAR_VALIDATOR previously used in this dialog does not allow chars used in path names, like / and on Windows \ and : )

Fix dialog title to be "Electrical Rules Checker" to match everywhere else.
Fix all usages of "Erc" to "ERC" consistently.
Move action buttons to bottom of dialog, make Del Markers actually say Delete Markers.
Add tooltips to ERC options matrix buttons to indicate what their current state is, for newb friendliness.
Cleanup ERC options code that for some reason decided to delete the button and recreate it instead of just updating it's bitmap directly.
Rename "Test Erc" to "Run" because you are running ERC and not testing it.
Fix improper usage of SetLabel on a wxTextCtrl instead of SetValue so the ERC totals now work!

fix recent bug which prevent eeschema to save color preferences.
fix few other minor issues.

IO_MGR::PCB_FILE_T IO_MGR::GuessPluginTypeFromLibPath() : better test for KICAD type footprint libraries: previoulsy, just test if a library name ends with .pretty, which is not enough.
GitHub lib names also ends  by .pretty, so also test if a lib name does not start by http (which could be a GitHub lib name).

Eeschema: back to KICAD_KEEPCASE option, to find parts in lib, when using case sensitive option (default).
Schematic component properties dialog: add 2 helper buttons to manage the chip name (name of the corresponding part in lib)
- a browse button to chose an other chip name
- a test button, to know if the part exists. If not existing, list the parts found when searching using a case insensitive comparison.

Kicad manager: fix an issue when starting eeschema from its button: if the library editor was previously running, and if the quasimodal field editor dialog was called, eeschema dis not start on Windows, or started but dis not load the schematic project on Linux.
Enhancement: if a tool is running but is iconized, clicking on its button bring the window on screen.

Eeschema: remove the compil option KICAD_KEEPCASE. Eeschema is now always case sensitive when seraching components in libs.
However to be compatible with old versions of Eeschema, when a search in library fails, a case insensitive search is made.
Therefore, this version should be compatible with sch files created by previous Eeschema versions compiled with KICAD_KEEPCASE = OFF

Factored out text ellipsing support to max 15 character (for generating menu items)

Eeschema: schematic libraries in a sub path of standard libraries paths are now better handled.

Eeschema: add dialog libedit options and move options relative to libedit from eeschema options to this dialog.
Ensure some values initialized by the schematic editor and used by libedit are also initialized in libedit even if  the schematic editor was not started.
Remove useless commands (save/load project config) in libedit, because now they have no sense.

* Refresh canvas when user cancels edits so that the discarded sheet is
  cleared from the schematic.
* Add file name validation to the sheet properties dialog to prevent
  illegal file name characters from being entered into the text control.
* Rename FOOTPRINT_NAME_VALIDATOR to FILE_NAME_CHAR_VALIDATOR for clarity.

  *) When kicad.exe closes a project, close any open KIFACEs so that they cannot
     get disassociated from their true PROJECT.
  *) Allow loading eeschema library editor from kicad.exe
  *) Allow loading pcbnew library editor from kicad.exe
  *) Rename LIB_COMPONENT to LIB_PART.
  *) Add class PART_LIBS, and PART_LIB.
  *) Make PART_LIBS non-global, i.e. PROJECT specific.
  *) Implement "data on demand" for PART_LIBS
  *) Implement "data on demand" for schematic SEARCH_STACK.
  *) Use RSTRINGs to retain eeschema editor's notion of last library and part being edited.
  *) Get rid of library search on every SCH_COMPONENT::Draw() call, instead use
     a weak pointer.
  *) Remove all chdir() calls so projects don't need to be CWD.
  *) Romove APPEND support from OpenProjectFiles().
  *) Make OpenProjectFiles() robust, even for creating new projects.
  *) Load EESCHEMA colors in the KIWAY::OnKiwayStart() rather in window open,
     and save them in the .eeschema config file, not in the project file.
  *) Fix bug with wxDir() while accessing protected dirs in kicad.exe
  *) Consolidate template copying into PROJECT class, not in kicad.exe source.
  *) Generally untangle eeschema, making its libraries not global but rather
     held in the PROJECT.

Remove a minor warning message in Debug mode for 2 dialogs.
Pcbnew: update Gerber X2 file format (File Attribute) to very last X2 specification
Eeschema: Fix a minor bug in block selection (sometimes the last selected component was select instead of items in selected area)
and better drag behavior when draging an item by the drag hotkey.

Eeschema fixes: fix  Bug #1348983 save cmp file crashes cvpcb when eeschema is opened (backannotation crashes). Happens only when some footprint names are not set (blank names).
Also fix incorrect backannotation when footprint names contain spaces (put spaces in names is always a bad idea)
* Fix minor Bug #1349058 Choose component dialog: Search field loses focus after entering a character and internationalize the dialog.
* Fix a subtle bug which prevent eeschema to read the project config file when launched from kicad manager, and when kicad.pro is not found.