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.

  Committing this separately from the rest to ease making a patch for just this
  functionality in case that it might make it into the trunk.
  
  This can function standalone, though it is less useful without the rest.
  It requires that wxwidgets-3.0.0_macosx_magnify_event.patch be applied to wxWidgets
  It is completely optional; everything is guarded by the USE_OSX_MAGNIFY_EVENT macro.
  
  - Added OnMagnify event handler to EDA_DRAW_PANEL, EDA_3D_CANVAS and the helper for
    EDA_DRAW_PANEL_GAL, WX_VIEW_CONTROLS. This should cover canvases all current tools.
  - Guarded all with USE_OSX_MAGNIFY EVENT feature macro and added support in CMakeLists.txt

Cleaning 3 svg files (no icon change)
Very minor other changes.

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.

Rework on env. variable KISYS3DMOD. Until now, was used in different files using different ways, so no consistency between files.
code cleanup.

Add patch from Mario Luzeiro to 3D viewer. Fix a serious issue due to duplicate ID used in menus and toolbars between sub-applications, related to wxUpdateUIEvent events loop.
wxUpdateUIEvent events can be sent to parent frames, when opening a menu in a child frame, if parent and child frame share same ID fro menuitems (or tools)
The wrong menuitem can be used in some cases ( because there are more than one menuitem with the same identifier), by a wxUpdateUIEvent event function run in a parent frame.

3d viewer: fix a (minor) bug when run from cvpcb or modedit: the footprint is now centered on Z axis
Better setup for lights, which gives a better rendering

3dviewer: back to double (from float) in class S3D_MASTER for 3 members (m_MatScale, m_MatRotation, m_MatPosition) which are used in dialogs and r/w file functions, which expect double.
Using float create minor but unwanted issues in  r/w file functions.
S3D_MATERIAL: enable all color options: if a 3d shape has bad color parameters, the shape must be modified, not the 3d rendering.
The rendering now matches what we see in other vrml viewer like FreeCAD.
Some minor coding style fixes.

3D viewer: move helper functions from 3d_draw.cpp to 3d_draw_helper_functions.cpp. Add comments in .h sources. Better management of background color. coding style fixes.

dialog_track_via_size: set minimal size  and make dialog resizable.
Update demo file.

3d viewer: Add high quality mode option is realistic mode (Shows holes in copper zones, but with longer calculation time)
Gal: fix a very minor issue: the keys to switch between copper layers are now - and + (according to the doc and the normall mode), instead of - and =

2) Change from legacy Cu stack to counting down from top=(F_Cu or 0).
   The old Cu stack required knowing the count of Cu layers to make
   sense of the layer number when converting to many exported file types.
   The new Cu stack is more commonly used, although ours still gives
   B_Cu a fixed number.
3) Introduce class LSET and enum LAYER_ID.
4) Change *.kicad_pcb file format version to 4 from 3.
5) Change fixed names Inner1_Cu-Inner14_Cu to In1_Cu-In30_Cu and their
   meanings are typically flipped.
6) Moved the #define LAYER_N_* stuff into legacy_plugin.cpp where they
   can die a quiet death, and switch to enum LAYER_ID symbols throughout.
7) Removed the LEGACY_PLUGIN::Save() and FootprintSave() functions.
   You will need to convert to the format immediately, *.kicad_pcb and
   *.kicad_mod (=pretty) since legacy format was never going to know
   about 32 Cu layers and additional technical layers and the reversed Cu
   stack.

This workaround was already used (bzr 4301, in file plot_board_layers.cpp) also to avoid similar crashes (uses 18 segments instead of 16 to approximate a circle by segments).
Minor code cleanup in dialog_plot.

In particular HitTest for zones *do not* select the nearest vertex/edge as a side effect

In particular HitTest for zones *do not* select the nearest vertex/edge as a side effect

- Converted the Next/Prev C casts to static casts and removed the type
  unsafe ones
- Splitted as virtual the VIA::Flip member instead of using RTTI
- Heavily refactored the 'unconnected track' cleanup routine
- Misc constification

3D viewer: Commit patch to enable the rendering of wrl files generated with Meshlab. See https://bugs.launchpad.net/kicad/+bug/804778