Added a few settings to make the layer settings more similar to KiCad defaults (moved vias to VIA_THROUGH_VISIBLE, added a few rules for required layers).

Added POINT_EDITOR::isModified().

Minor code cleaning.

* Handle different item global deletions correctly.  No more removing of text
  if graphics is selected.
* Layer settings are always obeyed for modules, zones, text, and graphics.
* Text will be removed from copper layers if all layers are selected or
  according to the current layer.
* Added check boxes for "normal" and "locked" footprints to be consistent
  with the naming for the track deletion options.

Commit patch about  cvpcb, pcbnew and layout editor menu items, with 3 menu labels modified in Eeschema.

EDIT_POINTs show up when there is only one item selected (now after deselection as well).

Selection clearing is invoked using TOOL_ACTION object rather than its name.

Fix also other very minor issues.
Realistic mode shows or not the copper thickness (depending on selected option in preferences) to speed up the screen redraw.

Fix for bug #1285878, build fails with clean repository and high parallelism due missing dependance between router and pcbcommon

TOOL_EVENT message is supposed to contain string as parameter.
Added missing header for class_drawsegment.h (KiROUND).
Renamed SELECTION_TOOL::containsSelected() to SELECTION_TOOL::selectionContains().

[MacOSX] Avoid race between cmake -E copy_directory, which triggers a build error when using an high parallelism

* fp_lib_table.cpp: fix an issue on Windows in ConvertFromLegacy: sometimes, because the comparison was case sensitive, lib nicknames  were not found, although  libs exist ( for instance if a path was given like f:\mypath instead of F:\mypath)
* getpart.cpp: fix a potential bug on a translatable string with has requirements in spelling.
* fix bug  #1066179
* kicad: fix erroneous labels in sub menus.