Replace assertEquals with assertContentsAnyOrder.

Fix test dependency on hash order, which is about to change;
Documentation updates.

[ejona, 2014-06-19 22:47:35]

This CL is a random grab-bag of things. The only assertContentsAnyOrder don't
look like they need to be changed because they are all singleton lists. Then
there seem to be random fixes and javadoc updates and using a fixed string
instead of HttpMediaType. What all is going on here?

Even if it was all concerning assertContentsAnyOrder, I would expect a
description about why the change was necessary, such as not assuming iteration
order of hash sets, or wanting to change collection implementation.

[ejona, 2014-06-20 21:02:37]

LGTM

Trying this again. It seems rietveld ate my reply yesterday.