example.ini: Add liveupdate invite quota to example.ini.
CSS: Separate mod-specific styles from accept/leave box styles.

This is for the subreddit moderator pages but applies to contributor
pages in liveupdate.  The little moderator shield icon is the only
moderator-specific style and so this is split up to allow the general
part to be shared.
Generalize .pretty-button to non-anchor elements.
DenormalizedRelation: add missing will_write decorators.
DenormalizedRelation: add support for TTLs.