Fixed SetCurrentContext() assert, that was firing on closure of pcbnew, when the OpenGL backend was active.

Pcbnew: fix issue in modedit, undo command: moved fields were not drawn afetr undo (due to incorrect flags state)
Fix incorrect initialization of lib names column in EDA_LIST_DIALOG. (Only the row 0 was initialized)

*) Add scripts/library-repos-install.sh for downloading *.pretty libraries and possibly using them.
*) Remove template/fp-* files, they are now at https://github.com/KiCad/kicad-library/template/*
   so they can be maintained by the library team.  However note that it is possible to break
   kicad-install.sh with uncoordinated changes to that github repo.

It is best to delete your ~/kicad_sources/kicad-lib.bzr directory before running kicad-install.sh
at this or any newer version relative to an older library repo.

* Replace illegal file system characters when reading legacy libraries to
  prevent FPID parsing errors and allow saving to PRETTY file format.
* Create validator to filter illegal file system characters from footprint
  name text edit controls to prevent issues when saving to PRETTY file format.
* Add missing source file licenses and some minor coding policy fixes.

Better GITHUB class header documentation, better eeschema library field dialog stretching and title.

Now footprints, after loaded by reading a netlist are grouped by sheets by the footprints spread function, and the grouping is better.
Rename 2 files. Fix minor issues. Clean code

   comment for GITHUB_PLUGIN which should flow into Doxygen output.
*) Rewrote: 
        PCB_BASE_FRAME::Save_Module_In_Library(): now uses fp-lib-table and PROPERTIES.  
        PCB_EDIT_FRAME::ArchiveModulesOnBoard(): now can archive to any writable library type.
        PCB_BASE_FRAME::SelectLibrary(): is now generic for selecting a library, not just the active library.

template: add file fp-lib-table.for-eagle

Pcbnew: Code cleaning and bug fix in autoplace functions
Dialog exchange footprints has now a separate button to update the .cmp file, only on request.

Pcbnew: Fix a crash on exit when an item was previously deleted. Fix not working footprint exchange functions

FIX: unique renaming of eagle footprints by substituting illegal : and / with URL encoding technique.
ADD: window resize border to DisplayError() windows.

* Make spacing between controls and dialog frame consistent.
* Use default size to allow wxWigdets to determine optimal dialog size.
* Set OK button as default so return key works properly.

* Use std::swap for PCB_LINE_T items in SwapData().
* Use std::swap for PCB_MODULE_EDGE_T items in SwapData().
* Add assignment operator to EDGE_MODULE object.
* Move code from copy method to assignment operator.
* Minor coding policy fixes.

*) Save library nickname in APP so upon module editor re-entry last is re-used.
*) Fix bug editing fp-lib-table Description field.