Remove support for tags, also remove the tags column from the member table.
Drop malicious_proof table
Further removal of malicious behaviour detection code.
Drop the malicious undo blacklisting from check_undo, just keep one of
the messages, and send the message back to the sender in case we are
keeping a different one.
Remove must_store attrs.
Remove obsoleted tests and fix the failing ones
Merge pull request #230 from whirm/flags_cleanup

Remove support for tags, also remove the tags column from the member table