Added checks to StrCmpNum() function in common/sting.cpp to prevent
iterating past the end of the sting. Also removed length of string
parameter since it did not seem to be used anywhere.
Fixes lp:1818157
https://bugs.launchpad.net/kicad/+bug/1818157
Be more intelligent about sorting lib tree items. (Footprint
entries, for instance, come out of an already-sorted list.)
Don't recreate menus twice when laoding Footprint Editor.
More pervasive use of WX_FILENAME to avoid expensive calls to
wxFileName::SplitPath() and string concatenation.
For POSIX kernels do all the work on the file-system side so we
don't have to keep converting back and forth between encodings.