Bug fixes

e42ebb5 Handle {meta del} in MessageVC.
ebbfd1f 63a3260 Use pagination in MessageVC to keep track of loaded messages.
51cca3b Clear account and SQLite sequences on logout.
6f4b296 Make new messages actually load when the user swipes down.
f0edd4c Fetch messages from server using Topic.missingRange.
f375fff Fix 'database locked' error upon logout.
e1f1397 Clear SQLiteDb upon logout.