Pcbnew: fix Bug #1373468 (Non Copper Zones Properties  dialog "Layer selection" empty) (Linux specific)

Pcbnew: add append board function, only available when Pcbnew is run in standalone mode (outside a project), to allow a basic panelization.
(this function is not compatible with a project, because it breaks the coherency with the schematic)

Minor other fixes.

Minor fixes: specctra export: skip malformed circles (having a radius = 0)  in board outline creation, which can crash 3d-viewer or vrml export.
dialog_fp_lib_table: remember during a session the last open table (global or local).
drawing_tool: fix compil warning
Update demos.

* Set wxGrid tab behavior to leave grid when using the tab key.
* Lots of coding policy fixes.

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 did not start on Windows, or started but sometimes did 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. This was already the case on Linux, but on Windows, the iconized frame was staying iconized.

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.

Patch for the Python footprint wizard helpers. This adds a few more drawing functions, such as for circles, and also uses a matrix-based transform stack with greatly simplifies constructing footprints consisting of regularly spaced elements (e.g. in lines, grids, circles, or some list of points that you specify).
This fixes bug #1366299

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

Ref and Value for footprints: use now the layer color, not a specific color: this is needed by the fact these fields can be on an other layer than silk screen, and therefore must have the corresponding color
Also do not allow copper layers, solder paste and solder mask: put Ref or Value on these layers has no sense, and can create serious issues on the board.

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

Since reference and value are not anymore always on silk changed the label on the corresponding options in the plot dialog
The 'proper Gerber extensions' was renamed in dialog as 'Protel Gerberl extensions': I don't know if it was a typo/misunderstanding or what but the proper extension is gbr; the set of alternative extensions seems to be the one used by Protel/Altium.

The members SetIgnoreMTextsOnCopper, SetIgnoreMTextsOnCmp,
SetIgnoreModulesOnCu, SetIgnoreModulesOnCmp in the collector guide are
renamed to the clearer SetIgnoreMTextsOnBack, SetIgnoreMTextsOnFront,
SetIgnoreModulesOnBack, SetIgnoreModulesOnFront

Modified the collector and drawing behaviour for text in modules as
discussed in the mailing list.

* Now module text on layers different than Silk should work! *

Still need UI support for setting the layer in the module editor.

- Removed the friends MODULE and FOOTPRINT_EDIT_FRAME from TEXTE_MODULE
  (as in the @todo comment)

- Refactored the Rotate/Flip/Mirror for text in modules into the
  TEXTE_MODULE class itself (members RotateWithModule, FlipWithModule,
  MirrorWithModule)

- New behaviour in coloring text on screen: reference and value still
  take the color from the MOD_TEXT_FR_VISIBLE and MOD_TEXT_BK_VISIBLE
  visibles; other text takes the color of the layer containing it
  (except when hidden, obviously) but still get its visibility
  controlled by those visibles (probably the most intuitive and useful
  behaviour)

- Still need to decide: should text on a layer be hidden when the layer
  is? Probably yes (still to be implemented);

- Some comment fixed and many cast converted to static_cast

Remove a minor compil warning in shape_collisions.cpp

- Reference is visible on silk and the corresponding assembly layer
- Reference is shown on assembly always on the component insertion point

Hidden references are not forced shown in assembly plots (there is
already a user option for that)

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

Kicad:  more understandable dialog when creating a project from template. Fix also a bug when copying and renaming template files.
Pcbnew: dialog to create new .pretty lib: fix an issue which prevent to open a full disk directory (at least on Windows)

* Create GetNewConfig() and GetKicadConfigPath() to unify configuration file
  creation and location.
* Move Windows configuration out of the registry into configuration files.
* Move Linux configuration files from $HOME to $HOME/.config/kicad to eliminate
  configuration file pollution in the users $HOME folder.
* Fix a bug in the configuration file where the Eeschema hot keys are saved.

Help files: can now be html or pdf files: Kicad search first for a .html help file, and if not found in a path, search for the corresponding .pdf file.
Therefore our .pdf files can be replaced at any time  by .html corresponding files in kicad doc/help sub directories.