Initial commit of actual program code

When this program is executed, it will connect to an IMAP server
for an account (which must first be configured; see the block of
constants at the top of green_shirt.py) and download all unread  messages
that have "[GREEN SHIRT]" in the subject. It will then attempt to
use Google Translate to convert the first 100 characters to speech
and speak it aloud. After processing all downloaded emails, it will
quit.
Added regular polling; filter emails locally

This commit does two things primarily:
  * The program will not quit after the first time downloading
    and playing available messages. Instead, it will sleep for
    one minute and repeat the process ad infinitum.
  * It no longer filters the e-mails by subject through a IMAP
    search criteria. For some reason, it took a lot longer for
    new e-mails to appear when using that criteria. We get near
    instant availablity by downloading all unseen e-mails and
    filtering them out on our own.
Handle messages longer than 100 characters by chunking them

We break e-mail bodies into chunks each 100 characters long.
We then convert all of them serially to speech and play all
of them at once. Unfortunately, mpg123 doesn't seem to be able
to play more than one mp3 through stdin. We have to call it
each time for each mp3. As a result (plus considering reading
and processing time for each mp3), there are gaps between the
chunks.

Additionally, we chunk at the 100 character boundary regardless
of what's there; we will often split up words.
Don't split up words when chunking long messages

If a chunk (except the last one) ends in an alpha-numeric character,
we'll move the end leftward until we hit a non-alpha-numeric character.
This isn't the smartest behavior, since it's possible that we happened
to split the chunk originally at a word boundary, but it does stop
us from spliting up words.
Filter out IFTTT's e-mail footer from the body

IFTTT's email channel adds a footer about the recipe used to
generate the email. This commit filters out that footer.
Strip leading and trailing whitespace from the body

That whitespace impacts our character count for TTS needlessly.
It'd be cool to eventually (TODO) reduce consecutive whitespace
as well.