Add test suite

[twitchyliquid64]

Need to have a test system to prevent regressions.

Per command feature tests ideal.

[alienscience]

There are pre-written tests if you are feeling lazy:

http://imapwiki.org/ImapTest

I have no idea if these are hard to integrate or not.

[twitchyliquid64]

Way too hard, they require compiling the entire of dovecot. Ill just write out our own.

Should be easy to hook the command interface to do unit testing at that level.