A bunch of the common_* functions for date formatting expect an interpretable string, rather than a Unix timestamp, as input. Switched to using the DB-formatted timestamps as we put them into the object rather than the unix timestamp intermediate value when formatting the plaintext and HTML fallback content.
The ShowNoticeAction subclasses were cut-n-pasting a lot of prepare() code from ShowNoticeAction, though the only part that's different is how we look up the notice. Broke that out to a getNotice() method, so only that needs to be copied. Avoids extra copies of permission checks and other common code in this spot.
Numbered parameters when more than one used in a message.
L10n updates for consistency.
i18n for non-translatable exception.
Updated translator documentation.
Removed superfluous whitespace.
* RSVP cancel/delete now works
* caching fix for RSVP insert and delete (compound unique keys aren't properly handled for pkeyGet's caching right now; hacked it for this class for the moment)
* div nesting fix
* missing name/avatar on RSVP responses
