cfme_data now autorandomizes certain values

- fixes #65
- See utils.randomness.RandomizeValues docstring for more info
- See utils.cfme_data.CfmeData docstring for usage
- Also moved loading of cfme_data file into a util function, example usage in updated test_vm_power_control
- Renamed cfme_data fixture file name to match the fixture name
- Given the mildly crazy things happening in RandomizeValues, I created unit tests for it in utils/tests
- Moved some other things around in utils