Move Barracks class into stationary units file
Isolate method for drawing target marker
Move drawing functions to separate file

This has highlighted a bunch of places where I was relying on global
access to certain variables.
Start basic configuration file/class
Make utility function for scaling tuples
Use new scaling function in rest of file
Rename scaling function to be more general
Use more pythonic array handling

This allowed me to reuse the scale_tuple function