Add in lower level commands to GCODE parsing

[zschwid]

Update GCODE parsing to enable the pi to generate paths more flexibly:

Suggestion:

• G10 (L0 X{L0 end X} Y{L0 end Y} Z{L0 end Z} .. L5 X{L5 end X} Y{L0 end Y} Z{L0 end Z} T{movement time}
• • Parses to enqueuing a straight line movement for each of the legs to the desired end motion at a speed that makes the movement take movement_time milliseconds to complete
• • Any legs not mentioned in the command should be automatically filled in with an enqueued wait of movement_time milliseconds