unused datafile report must now be requested

While the UDF report is useful, it is only useful after a complete
test run. The --udf-report flag has been added to allow manually
enabling the report in that case.
fix chargeback tests
Merge pull request #132 from seandst/unused-datafiles-flag

unused datafile report must now be requested
Script for controlling providers from the command line

Also added support scripts:
- utils/credentials.py, analogous to utils/cfme_data.py
  (in fact, a copypasta)
- providers utils to help mix in cfme_data and credentials knowledge to
  get a provider instance based on cfme_data name alone
smoke and requires_test markers

smoke mark moves smoke tests to the top of the test run
requires_test can mark tests as requiring another test (like, say, smoke tests)
Merge pull request #140 from dajohnso/fix_chargeback

fix chargeback tests
Merge pull request #135 from seandst/provider-tools

Script for controlling providers from the command line
Merge pull request #136 from seandst/smoketest-mark

Smoke test marker