Bugfixing, template improvements, translation updates.

- Fixed #649: Clean old motion fragments in template and pdf (about motion notes).
- Fixed motion pdf issues: missing submitters, voting result and make motion state translateable- Added post_save function also for UserUpdateView.
Fixed #680 (Open all PDFs in new tab).
Motion import improved:
- add semicolon support (use utils/csv_ext.py as participant import)
- show all warnings of each line in one warning message
- show success message with total counter (x of n motions imported).
- improved warning and error strings