Twitter: Add twitter bot.

Update corresponding files.
Twitter Bot: Tweet new events.
Photos API: Use delete() on query for faster deletion.
Parts API: Minor PEP8 fixes.
Travis: Add twitter keys.
Twitter: Use twython instead of python-twitter.

Now we can upload photos to twitter.
TwitterBot: Append a string properly.
Don't need caneiusepython3.
Merge pull request #220 from CalPolyIEEE/tweet-event-updates

Tweet new events from the landing page.