Add is_personal, is_outgoing columns

Also drop realm. It's pointless. Hopefully that'll save a little bit a space
after adding a new index.
Synchronous filter.js from roost-client
Formatting
Allow is_personal filters
Rename zuser to zutil
Stricter checking on subscriptions

Don't allow NULs.
Implement send with outgoing messages

Or at least an initial version. Laundry list of things to be dealt with later.