Standardize on assertEquals as a stepping stone

The next step will be to convert assertEquals to a plain old assert.
Remove ', actual' from asserts in tests

I adopted the practice of appending `, actual` to assertions in testing
because nosetests doesn't give us rich assert comparisons by default
(probably they do in a plugin?). We don't need to do this anymore.
Convert assertEquals to assert statements

Plain assert statements are less cumbersome and more natural than method
calls.
Convert remaining assertEquals calls

These were split over multiple lines so the regex I used to sed the
first batch didn't catch these.
Convert assertTrue to plain asserts
Merge pull request #1504 from gittip/plain-asserts

Clean up asserts in testing