Send a message when there's an unhandled exception

this fixes #3
fixed issue where DMs would fail to send if they were too long; now we just clip to 140 chars.
ignore buffer on launch. fixes #4
removed unused references to 'overflow'
moved streamhandler to its own file

- related cleanup
- removed unused imports
- fixed some documentation
stream handler prints *current* (not max) buffer size on close
actually check our DMs every once in a while (or 5 minutes)
reduced buffer size, added a comment
hotfix
added coding to datahandler
hotfix
actually crash on exceptions after sending DM
maybe I can't catch all exceptions :-(
no longer try to preserve any elements in buffer on reset
moved buffer length check to appropriate part of loop
increased buffer ignore duration
catch urlerror in twitter handler, handle exceptions again

- use sys.exc_info() to print/log exception backtraces
- try to resume after exception
- send DM after exception
comment
tweeks to some buffering related constants

increased time from launch until we respect our buffer
increased overall buffer size
fixed tweetfetcher