djblets.util.tests was getting a bit large, and was only about to grow

larger with some upcoming changes. In order to keep things more sane,

this change splits the old tests file into a series of new files, and

moves the tests inside djblets.util.templatetags.tests into this

namespace.
As many of these are from the early days of Djblets, most of these tests

were also using very outdated naming and styles. They've all been

updated for the modern style guidelines and to take advantage of modern

unit testing functions.

Unit tests pass.