Probing command gets stuck in hold if several g38.2 are submitted
Ex.
G0 X0 Y0 Z0
G38.2 Z-10 F100
G10 L20 P0 Z0
G0 Z2
G38.2 Z-1 F50
G10 L20 P0 Z0
G0 Z2
G0 X0 Y0
G38.2 Z-1 F100
G0 Z2
Added Probing to Mega2560 and fixed Shapeoko2 compile error
Merge pull request #373 from EliteEng/dev

Added Probing to Mega2560 and fixed Shapeoko2 compile error