added MingW compile changes
Merge branch 'refs/heads/rob' into alden
023.06 Fixed problem in structure definition in canonical_machine.cpp
024.01 Set default profile for ABC axes to mirror X axis settings for testing
Initial work on SPI (for SAM).
Working on USB. Ignore for now.
USB is working now. Needs cleanup.
Merge branch 'refs/heads/alden' into rob