Use austerus-send in stream mode

This mode will allow lprng to read status.
Basic start of planner code loading depositions

The directory defined in PLATE_PATH contains a file generated from
auterus-verge in deposition mode for each object that exists on the print
bed.
Add basic plotting to SVG

The makes development of the planner easier as everything can be visually
debugged.
Introduce argument parsing and make writing SVG optional
Exit with non-zero status on error condition

The codes will be as follows:
0 - Able to print as is.
1 - Able to print shifted.
2 - Unable to print.
Implement Deposition.from_str() method

Need this when using austerus-verge as a subprocess.
Split Deposition class into several subclasses

The base class is Region.

Deposition is still used for depositions on the plate but new classes are
introduced for new print head movements etc. These need to take the safe
working bounds of the head into account, this will be implemented later.
Use alpha to make all Regions transparent

This makes the planner SVG easier to understand.
Be less verbose by default
Add some comments
Move Z safe height calculation to be with collision detection

Cosmetic change, just keep all the processing together.
TODO: Restore
TODO: Implement head area aware class
TODO: Add new print region
TODO: Implement safe reset region