Bigger changes.. full_virtual_size was removed from index record and MessagePart caching is now forced. Also added per-message flags, including binary flags which can be used to check if CRs need to be inserted into message data. Added mbox-rewrite support which can be used to write out mbox file with updated flags. This still has the problem of being able to read changed custom flags, that'll require another bigger change. There's also several other mostly mbox related fixes.