RFE: Implement localization / language system

[ryran]

I didn't design Pyrite with localization in mind -- the modules/messages.py file contains the bulk of what would require translating; however, there are other user-facing messages peppered throughout the code. In order to make translation more feasible, some serious code re-factoring/re-organization needs to happen. I'll be looking into this.

[pryds]

If this gets into place, I'd be happy to provide the Danish translation.