Updated the invoke_url to properly handle attachments.
Made a couple methods to access the attachments and keep the code clean.
Changed the way we handle list so that it can accept multiple args.

This is handy when listing timeline attachments.
200 as an arg is redundant so I removed it.
added params as an arg to handle timeline attachments.
bumped the version.
Cleaned up some of the old tests.

typos, wrong calls, and statuses.
Created all of the tests for timeline attachments

@ciberch Note that I did not write the tests for insert. I have not
uploaded files through rest-client so I would appreciate assistance
there.
Fixtures for timeline attachments.
Updated the attachments and attachments_id methods to make them simpler.
changed args[0] to args.first because we might as well take advantage of this fine ruby language we have at our disposal.
Merge pull request #31 from ciberch/timeline-attachments

Timeline attachments