Correct a few translation strings

They weren't using dicts for parameters to work around the ordering
issue.
Transifex update
Update AUTHORS file

Using *secret" formula for who's a contributor
Add mailmap file to identify users with different email/names

This is useful for git shortlog - see:
http://simonharrer.wordpress.com/tag/git-shortlog/
Slight reorganisation of sandbox settings
Update CSS docs (they were stale in places)

Fixes #709