* Replace use of wxICON by new icons declaration.
* Remove unused files.
* Fix filenames inconsistencies between old and new icons.
* dialog_erc handle variable size icons in erc matrix.
Remove or move old .ico and .pgn files and add new icons (.ico files and .png files) in bitmaps_png/icons and bitmaps_xpm/icons
.png files and .ico are used to build desktop shortcuts
Handle variable size bitmaps in kicad.