Pressure (thickness) of lines and rectangles too thin and not configurable

[goatchurchprime]

There's a const PRESSURE := 0.5 hardcoded in the RectangleTool and CircleTool, and this value itself is hardcoded as an immediate value (as 0.5) in the LineTool

This gives a default thickness for lines that is far too low in my opinion when you're mixing lines and painted drawings just to do straighter lines.

[tafode]

@goatchurchprime Since this feature has been missed by several users (see bug #252 and #216), I have created a small prototype and wanted to ask if this would be usable for you?
https://youtu.be/qWqjiMVRzwo

@mbrlabs Would this way of configuration also be ok for you? If so, I would clean up my code a bit and create a PR.

[mbrlabs]

Hello, sorry for the delay. Yeah, this looks good!