* Add dialog to edit the list of active equ files.
* allows use of our environment variables in .equ file names.

Add hight contrast option in Modedit. In hight contrast mode, solder masks and solder paste are shown.
this option was possible only by modifying the way display options are managed.
before these changes, display options were a global DISPLAY_OPTIONS class instance.
Now each EDA_DRAW_FRAME(and derivated classes)  includes its own DISPLAY_OPTIONS class instance.
As a consequence, some duplicate display option variables in these classes have been removed, because there were just duplicate variables of the  DISPLAY_OPTIONS class instance.

Modedit: now shows a specific layers manager, which allows user to select the technical layer which is used when adding a new graphic text or outline to the current footprint.
Please, note the layer manager was already available in GAL mode, but is was the same as tne board editor, which is not good.
Now:
- In default mode or GAL mode, the look is the same.
- Only suitable technical layers (i.e. paired layers) are selectable from the layers manager (for special purposes, some other layers can be used, via the graphic items properties dialog)

* With fixes from Adam Wolf.

Pcbnew: better display of tracks/vias/grid in toolbar. All: modify the zoom value shown in toolbar or status bar (roughly now zoom 1.0 is near the 1:1 scale, on a 22 inches Monitor). Fix also many other minor and very minor issues

* Change Read to Load in Pcbnew and Eeschema preference menus.
* Make electrical rules check status bar message the same for both the menu
  and toolbar entries.

Update ecc83 demo. default KISYS3DMOD definition on Linux: add /usr/local/kicad/share/kicad/module/package3d test to find a suitable value.

Cvpcb: force project name in stand alone mode, to allow access to project fp lib table. In project mode: disable the read netlist option (the netlist is read when Cvpcb is started by eeschema)
Dialog fp lib table editor: now shows the table full filenames, to help users.

Remove a duplicate code for dialog select dir list.

Page layout selection: fix Bug #1405972, and add minor enhancement in page layout selection dialog (the new layout is shown after selection).
When the filename is not absolute, the page layout file is now searched first in project folder, and then in kicad template folder, if not found in project.

Fix issue when using a page layout file in project folder: eeschema and Pcbnew did not use it, unless using an absolute path.
Now, if the file path is not absolute, it is seen as relative to the project (which is the expected behavior)
fp lib wizard: when pcbnew id compiled with USE_GITHUB_PLUGIN=OFF, the github plugin option is no more accessible (and the web viewer no more used).

Fix issue when using a page layout file in project folder: eeschema and Pcbnew did not use it, unless using an absolute path.
Now, if the file path is nor absolute, it is seen as relative to the project (which is the expected behavior)
fp lib wizard: when pcbnew id compiled with USE_GITHUB_PLUGIN=OFF, the github plugin option is no more accessible (and the web viewer no more used).

Freeroute dialog: remove freeroute access via java web start, because freeroutecanot be run now via java web start.
freeroute.ja rcan be run by Kicad, as long as freeroute.jar is found by Kicad (for instance if it is in kicad bin folder)

Freeroute dialog: remove freeroute access via java web start, because freeroutecanot be run now via java web start.
freeroute.jarcan be run by Kicad, as long freeroute.jar is found by Kicad (for instance if it is in kicad bin folder)

Fix install issue after removing freeroute.jnl, now useless because freeroute is no more accessible via the web.
(Kicad is still able to run freeroute if freeroute.jar is accessible)
add wxWidgets-3.0.2 folder detection in FindwxWidgets.cmake

Fix install issue after removing freeroute.jnl, now useless because freeroute is no more accessible via the web.
(Kicad is still able to run freeroute if freeroute.jar is accessible)
add wxWidgets-3.0.2 folder detection in FindwxWidgets.cmake

FindwxWidgets.cmake: fix missing webview library name in library list to analyze. this fixes missing symbols issue in winbuilder.

Add a wizard to the footprint library table dialog editor, to help users to select the right plugin, an existing enviroment vairable or an absolute path, and addl a list of new entries to the table.
Note: the wxWidgets webkit/webview library is needed.
On windows,there is no problem.
On Linux,  the libwebkitgtk-dev tool (sudo apt-get install libwebkitgtk-dev)  must be installed if it is missing (and wxWidgets rebuilt).
However, to avoid use of wxwebview, you can compile kicad with cmake option -DKICAD_USE_WEBKIT=OFF.
But the github plugin wizard will be not available.