* 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.

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.

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.

*) Move button handlers to LEFT MOUSE CLICK from COMMAND events, so wxGrid focus is not lost.
*) Sketch out the concept of COW support for the GITHUB_PLUGIN in its @todo.

more DIALOG_FP_PLUGIN_OPTIONS work, make PROPERTIES a map instead of a hashtable for alphabetical iteration.

*) Use it on 3 grids total in DIALOG_FP_PLUGIN_OPTIONS and DIALOG_FP_LIB_TABLE.
*) Fix bug when pasting "(fp_lib_table" text into FP_LIB_TABLE.

template<> -> template <>
Some more reformatting according to uncrustify results.

*) Set environment variable KISYSMOD before loading FP_LIB_TABLE so that
   FP_LIB_TABLE::ROW::SetFullURI() can do substitution up front.
*) De-emphasize the lib path in some of the footprint frames but keep it
   so the footprint editor can export a current library to another.
   You can even export a GITHUB library to a pretty library for local 
   installation.
*) Start the PLUGIN options editor.
*) Enhance cursor positioning in DIALOG_FP_LIB_TABLE.

We can now remove a few calls to FP_LIB_TABLE::ExpandSubstitutions( const wxString& aString )
since its being done in above function.

DIALOG_FP_LIB_TABLE now handles table to copy cut copy paste from global to
project and reverse.  Fixed a problem with cursor position management when
switching between tables.

CTL+X, CTL+V, CTL+A, CTL+C

Remove tooltips from fp_lib_table wxGrid, were annoying and munging wxGrid's grid.
Change initial size of DIALOG_FP_LIB_TABLE.

Paste popup menu in this dialog now allows pasting a (fp_lib_table)
s-expression element holding (lib) elements.  This provides an 
opportunity for GITHUB library publishers to put the table description
into their README.md file as a (fp_lib_table) element where it can
be quickly copied to clipboard and pasted into the fp lib table dialog.
This is a paste operation, and overwrites from the initial cursor position.

Fix throwing of IO_ERROR in plugin.cpp by converting function name to wxString.GetData().
Switch to const PROPERTIES* in GITHUB PLUGIN functions.

Add const PROPERTIES* to FootprintDelete().
Add {Get,Set}Properties() to FP_LIB_TABLE::ROW.
Touch up fp table dialog.

Fix an annoying issue about not named nets:
now, these nets are named from the component references and pin names which are connected.
therefore, unless the net or the footprint references are modified, the net name is not modified between 2 netlist calculations.

Write parser and formatter for options.  Write dialog verification used before saving
FP_LIB_TABLEs, triggered from OK button in table editor.
Switch PROPERTY's value column to std::string from wxString.
Add event handler to fp lib table dialog for upcoming options dialog.

Other platforms to follow as volunteers test support and get openssl in 
place.

* Make footprint viewer work properly with library table.
* Fix bug in Eagle plugin when enumerating footprints.
* Add missing P-CAD plugin from footprint library table editing dialog.
* Fix bug in FOOTPRINT_INFO::LoadLibraries when error occur loading footprints
  from libraries.

Fix minor bugs in cleanup dialog options and plot solder mask function (thanks to Lorenzo to locate these bugs)