Refactor things and fix the spaghetti

[taotriad]

All libraries should be refactored to remove the worst cases of spaghetti code.

Desired outcome:

• Executables and their includes should be able to be installed according to FHS on a Linux system.
• It should be possible to build .deb packages that follow the Debian packaging policy for python software.

[dweineha]

Additional requirements:

• Libraries SHOULD not call sys.exit() or print messages; they should raise exceptions, and wherever feasible use strings formatted with List[ANSIThemeString] as extra arguments to the exceptions (only works for our custom exceptions).
• Libraries MUST not have circular dependencies; define acceptable dependencies and stick to them

[taotriad]

This is WIP.

[taotriad]

While refactoring has not been fully completed yet, the systempath branch should now support installing to, and working from, the system path. There are probably still things to consider, but we're close to the point where we could consider creating .deb packages.