Convert tests to HTTPretty and reorganize

There are a lot of problems with the current means of mocking. Most
annoyingly is that we cannot differ the call to the request library by
even a single optional header or whitespace difference without breaking
the mock. HTTPretty does a better job of this because it only cares
about what is transmitted over the socket.

Rewrite tests so that they no longer do string comparisons of JSON encoded
dictionaries. This meant that they had to order the dictionary before
encoding and would fail tests where the ordering was not followed.

In the process of this I reorganized the inheritance of the
utils.TestCase object so that there is a clear separation between the
data stored on the V2 and V3 base test objects.

Change-Id: I590df65adb1d2177b4be4e016708db05131b6880
Merge "Convert tests to HTTPretty and reorganize"