Backport docs highlighting check monkey-patch for Sphinx starting from v0.6.6

Currently host that builds documentation uses Sphinx v1.0.7.

This monkey-patched tested with Sphinx (few) versions starting from v1.0,
because Buildbot's master/docs/bbdocs/ext.py depends on features
introduced there (Sphinx Domains).
Fix highligting issue with Sphinx 1.0 (and in 1.0.7)

Old Sphinx versions not highlighted unparsable Python code (new one
does).
Fix typos: "defered", "accecpts", "atomicitiy"
check that configured cache sizes are >= 1

LRU cache implementation assumes that the cache is at least 1
element large. Catch invalid master configurations where cache
sizes less then 1 are specified.
Replace use of deprecated unittest.TestCase.assert_() with assertEqual/NotEqual etc methods

If newer version of unittest will be used, self.assertEqual(..., None)
should be replaced with self.assertNone(...), same with not equal to
None checks.
Merge branch 'backport_docs_highlighting_monkey_patch' of git://github.com/vrutsky/buildbot
Merge branch 'typos4' of git://github.com/vrutsky/buildbot
Merge branch 'replace_assert_in_CVSMaildirSource_tests' of git://github.com/vrutsky/buildbot
Merge branch 'check-cache-sizes' of git://github.com/elmirjagudin/buildbot