Gerbview: support for plot lines (currently: not arcs) with a rectangular pen (Yes, it exists!). pcbnew: try to fix an issue when exporting arcs in gencad.

Gerbview: Added support for gerber command   SR (Step and Repeat) and multiple MOIN and MOMM in file

Gerbview: added  support forSF  (scale factor), IO (Image Offset), OF (Offset) and MI (Mirror) commands.

Fixed a bug about Aperture Definition having parameters for an aperture macro. See Changlog for not yet supported RX274X commands. Having still problems with arcs in some gereber files.

 Known bug: aperture macros having parameters are incorrect: parameters are not transmited correctly. Work still in progress.

Added an experimental tool to create logos from .bmp bitmaps. Added Potrace library to convert bitmaps to polygons

Added sample gerber files for test (gerbview has problem with 2 files)