* Fixed typo in docstring for 'failUnlessAlmostEqual()'

* Removed unnecessary use of 'float()' for time values.

* Removed apparently unnecessary import of unittest. At some point in
  the distant past I believe it was necessary otherwise the 'TestCase'
  that a module saw was not the same as the 'TestCase' seen within
  'unittest', and the user's TestCase subclasses were not recognised as
  subclasses of the TestCase seen within unittest. Seems not to be
  necessary now.