Update test deps to use unittest2/mock

In order to get some of unittest assertion methods in
python2.6 we have to use the unittest2 module instead.
Pass in auth handler to endpoint class

This makes it possible to create an endpoint
object with a custom auth handler.

Also added unittest for get_endpoint to ensure
I didn't break anything.
Merge branch 'pass-auth-handler' into develop

Closes #24.

* pass-auth-handler:
  Pass in auth handler to endpoint class
  Update test deps to use unittest2/mock