Post-processor and optimizer (Command Refactor - Part 3)

[giannissc]

• Modify __str__() of commands to print all the parameter that they hold instead of printing valid gcode and update tests
• Move CommandVector to address.py and rename to AddressVector
• Introduce post_processor and optimizer classes
• Optimizer methods:
  • remove_any_axis()
  • remove_optional_axis()
  • remove_modal()
  • remove_feed()
  • add_space()
• Optimizer tests
• Post-processor methods:
  • rapid()
  • line()
  • arc()
  • home_position()
  • safety_block()
  • start_sequence()
  • stop_sequence()
  • program_pause()
  • tool_change()
  • header()
  • footer()
• Post-processor tests:
• Implement to_gcode() in post_processor and update tests

[giannissc]

grbl supported commands:

Modal Group	Member Words
Motion Mode	G0, G1, G2, G3, G38.2, G38.3, G38.4, G38.5, G80
Coordinate System Select	G54, G55, G56, G57, G58, G59
Plane Select	G17, G18, G19
Distance Mode	G90, G91
Arc IJK Distance Mode	G91.1
Feed Rate Mode	G93, G94
Units Mode	G20, G21
Cutter Radius Compensation	G40
Tool Length Offset	G43.1, G49
Program Mode	M0, M1, M2, M30
Spindle State	M3, M4, M5
Coolant State	M7, M8, M9

Supported Non-Modal Commands
G4, G10 L2, G10 L20, G28, G30, G28.1, G30.1, G53, G92, G92.1