- get_message_list() will disconnect and reconnect POP3 box
- add UID to non-cached drivers, help clients to recognize messages
- move IMAP UID cache to non-cached driver
- fix message size (put it in cache)
- XXX : fetch body in nntp do not use generic_fetch_body
- add flags prototype to add or remove flags
- cache bodystructures
- search is not implemented
- list of folder new implementation
