gitian: Bump miniupnp version to 1.9.20140701

Also change build system: STATICLIB is now MINIUPNP_STATICLIB.
doc: Add list of contributors to 0.9.3
qt: Language update for 0.9.3
doc: mention translations in release notes
Add deeper XML checking to update-translation script

- Catch problems such as mismatched formatting characters. Remove
  messages that can give problems at runtime.

- Also remove unfinished/untranslated messages, they just take up space
  in the ts and waste parsing time.

Fixes #4774.

Rebased-From: da59f28
Rebased-By: Wladimir J. van der Laan
Filter translations through new update-translations script

This does not add any new messages from transifex, it just filters the
current ones.