Working on issue #29.  Added a suite module with a GreenTestSuite class that works like TestSuite in Python 3.4 and has the place for green-specific behavior stubbed out.  In this commit it is fully integrated into green, but acts the same as TestSuite.
Functionality seems to be working nicely in manual run-throughs.  Time to fix broken tests and write some new ones.
Made ProtoTestResult and GreenTestResult both inherit from BaseTestResult so I didn't have to duplicate functions that they both need identically.  This fixes the tests that broke (the subprocess ones).
Better refactored the BaseTestResult class.
One test!
Another test.  Almost there.
Massaged docstring.
Another test, another better design.
Yet another test, yet another improvement.  Captured stdout from passing tests is now displayed _before_ the list of tracebacks.
Solved the very vexing crash that for some reason only showed up on Windows.
Fixed python3 compatibility.
Fixes #29.