Added and Updated sw examples

Hello Neil,

Added and updated sw examples. For Xdesign mainly but it may also useful for the class too. Please merge to the branch for production.

The changes include - programs/machines:

1. Add Epilog/cut sw
2. Add Roland/mill/SRM-20/PCB sw
3. Add Roland/vinyl cutter/GX-24/cut sw
4. Updated ShopBot/mill 2D sw

modules/connect/svg:

1. Add SWExtractFaces,
2. Add SWPCB,
3. Add SWSelectFace

Not sure why git restored modules\toolpath\machines\laser cutter\Epilog to this branch. I don't think I have changed anything on it.

thanks, Shawn