Write a script to copy shared Python libraries to each program's `libs` subfolder when changing something instead of manually doing it + extract most of the settings and theme-loading code in `main.py` files out to separate libraries (would need basic stuff like a small class to not break things but most will be pulled out).

[DrewNaylor]

(Copied from #236) What I should do is have a "real" version of shared/reused libraries and just have a script that copies them to each program's libs folder. Then the copies in each folder that aren't the main one would be gitignored. I'd still need to have a message in the readme where it says how to run stuff to run a script to copy the libs into each subfolder. This would also allow me to pull out the settings and theme-related code from each main.py file instead of copying everything every time I make a change. Would also help other developers too, but they'd probably find it easier to just copy the libs folder manually instead of editing the script. I'd also have to change stuff so the path to the themes folder can be modified in case a program is not in my folder, but my goal is to have themes be installed to /usr/share/themes and the home folder version, so I'll need to change my paths when it's ready to be released.