Making an Add-on for Precision Drawing Tools (CAD)

[ermo]

@clockmender

I have also added a load of Docstrings to the code, but need to work on these with the help of @ermo who has kindly offered to help with this project, inputting his considerable talent and long experience with Python and more modern programming techniques.

Just wanted to clarify that I don’t necessarily agree with the “considerable talent” characterisation. So far, my contributions have mostly been of “janitorial” character.