TweepError was not imported in parsers.py, leading to "global name 'TweepError' is not defined" errors
Parser now sets source_url consistently.
Ignore any arguments that are None.

Fixes issues #33
Runtime exception in listener no longer fails silently (Fixed issue #14).
Changed url.
Fix for null twitter json objects.

Don't die while waiting for fix to twitter api issue 1823: http://code.google.com/p/twitter-api/issues/detail?id=1823
memcache cache
Added filtering by locations to the streaming API.
Now push lat/lon with only two decimals after the digit, like Twitter wants
Stream now accepts an authentication instance.

It should now be possible to authenticate with
the streaming API by either using BasicAuthHandler or
OAuthHandler.
Allow for secure streams and make sure to properly apply auth for OAuth.
Clean up the way we pull in stream options.

Note: this may break some code that just passes this options
by position rather than keyword.
Remove un-needed import and tiddy up some comments.
Open the correct type of HTTP Connection based on the scheme being used.
Update Contributors file.
Move tweepyshell script to tools folder.
Consumer credentials must now be provided to run oauth tests.
Fix a bug in the cache code which would error when loading non-Model objects.
Use unicode for Tweepy error messges.

Closes #38
Add include_rts parameter to user_timeline().

Closes #48