Locale cleanup

Did some housekeeping on the qt locale files:

- Fix wrong capitalization in wallet encryption warning message (cause: evil s/bitcoin/Dogecoin/i ???)
- Disable parts of update_translation.py:
  - Disable transifex process because we don't use that right now
  - Disable removal of unfinished tags because we have manual translation going on
  - The rest is all awesome
- Fix translation sprintf and qt string formats: the update script gave a lot of formatting errors, eg ```1%``` instead of ```%1```, fixed those.
- Clean up all locale .ts files: after all parsing errors were fixed, I ran the update script and it took care of some optimizations for us :)