Adding convenience methods to reduce test duplication
Add comments
Adding deep compare
Changes to names based on code review
Merge pull request #201 from jamiehannaford/test-helper-convenience

Adding test helper functions
Initial implementation of MarkerPage.
Use closures to count and mark.
Adjust callers to match.
Use base structs and embedding.
Move pagination to its own package.
Change identity endpoints and services.
Update acceptance tests.
Rename `LastMark` to `LastMarker`.
Rename "Self" to "Owner".
Turns out I can eliminate NewXyzPager funcs.
Adjust callers again.
Allow implementation code to specify headers.
Paginate the results of containers.List().
Update the acceptance tests to use pagination.
Paginate the objects.List call.