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.

Save document file when creating new component library from component in library editor. (fixes lp:1351952)

* Remove redundant number from unit context menu.
* Use letters instead of numbers in component edit dialog.

Pcbnew: fix Bug #1404191 (Zone filling fails when a zone inside having the same net and a highter priority exists, which is allowed to manage different fill parameters )

Allows use of modifier shift key with letters A ... Z  in hot keys (including hot key editor). Thanks to John Bird, who helped me with his patch.

Road map: Gerber X2 file function extension marked done in Pcbnew and Gerbview

Minor fixes. Remove unused icon. Add 3 new icons. Change one icon (3 icons are from Konstantin Baranowskiy)

* Make patches/wxwidgets-3.0.2_macosx_yosemite.patch usable.  There were
  complaints here before that the patch does not work because it is a
  "metapatch" that tries to patch another patch (which is not in the tree
  and therefore fails). With this change, it becomes a normal patch again,
  that can be applied to the wxWidgets source tree as described in
  Documentation/compiling/mac-osx.txt.
* Make scripts/library-repos-install.sh compatible with OSX: This involves
  checking for the correct option to enable extended regular expressions in
  sed during detect_pretty_repos, as the script uses "-r", which is only
  available in GNU sed. The sed shipped with Mac OSX is an older BSD descendant
  sed which needs "-E". This change has been tested to work on Mac OSX 10.10.1
  and on an up-to-date Arch Linux.  I also changed the error message during
  --install-prerequisites to inform users without apt-get or yum which programs
  need to be installed to use the script.
* Add the execute flag to scripts/osx_build_wx.sh: At the moment, after
  fetching the source with bzr, one has to chmod the file by hand. This
  change change ensures consistency between the script and the build docs
  for OSX, which assumes the script to be executable.