Added in basic support for Companies based on the dicussion in #10
The basic usage to set a user's companies is...

	user = User(email="foo@bar.com")
	user.companies = [
    		{"id":6, "name": "Intercom", "created_at": datetime.now()},
    		{"id":7, "name": "GitHub", "created_at": datetime.now()}]

	# Inspired by the ruby client.
	user.company = {"id":6, "name": "Intercom", "created_at": datetime.now()}

As the Intercom API does not support returning company info, an AttributeError is rasied if the getter of the company/companies properties is called.
Added in test coverage for the new Company object and company setters.
Fixed a bug which prevented User.delete() from working.
Intercom._call was not expecting the DELETE method when constructing request data parameters.
Hence, the params were being skipped over and the request didn't correctly register with Intercom's API.

Added in intergration test to check this is working as indetented.
Before,
The user returned would be the 'bob@example.com' not the email specificed ('to-delete@example.com' in the tests case).
Now,
The user info returned corresponds to the email specified ('to-delete@example.com') as we would expect, as Intercom API 'Returns the deleted user on success' (as according to their docs).
Changed tests to not use self.assertRaises like a context manager (e.g. 'with self.assertRaises...') to enuser python 2.6 test compatibility. Added self.fail() to try expect statements for points that should be reached as an exception should occur.
Fixing doctests to run against latest Dummy API.
Removing color from tags.
Basic setting support for Companies
Fixing company doctests.
Use DELETE for User.delete()