More tests and improvements to test machinery for futurize
Bump version to v0.7.0-dev
Update imports.rst doc to reflect separation of imports for disabled Py2 builtins
Doc tweak re internal API (int moved)
[Draft commit]: futurize: separate out fixes into stages 1 and 2
Clean up docs for standard_library and http/client.py diff
Improve futurize imports

More tests passing ...
Improve libfuturize fixes and tests