Bug 900519, part 4: Move SMTP to a module, r=Standard8

--HG--
extra : rebase_source : 6773a8dddfaf205f6868f35e2e9a30f718efe704
Bug 900519, Part 5 - Move POP to a module, r=Standard8

--HG--
extra : rebase_source : 3efdc1f771f3639aa858d278a8d8afac3ba6b7d8
Bug 900519, part 6 - Move IMAP to a module, r=Standard8. Bustage fixes for a CLOSED TREE.

--HG--
extra : rebase_source : 285fe5cb395135b3112b7ff53bc9b76db49974be