Add a 'debug' catalog & PEP8 the long string file

• Adds a function to generate a 'debug' catalog. This prepends 'X_X ' to strings, to make it obvious in-game which are translated and which aren't, while still remaining usable.
• cleans up the code and formats to PEP8 properly (except for line lengths).

Differential Revision: https://code.wildfiregames.com/D3617