Remove mock stdout. Nosetest captures stdout by default.
Change the capture() context manager to tee output.
Rename capture context manager and use new-style classes.
Have Capture grab both stdout and stderr.
Convert tests on stderr to use Capture context manager.
Merge pull request #837 from candlepin/awood/test-output-fixes

changes the capture() context manager so that instead of hoarding the output, it tees it