Update to Twitter URL pattern.

Currently we only handle URLs like:

    https://twitter.com/JonathanAquino/status/332855223402000385

This patch also allows URLs like:

    https://twitter.com/JonathanAquino/statuses/332855223402000385

which are also valid.
Merge pull request #60 from JonathanAquino/twitter

Update to Twitter URL pattern.