* fixed annoying recursion in exception handlers (fake_env and sand_env)
* "pubs git" always not quiet
* color option for git ouput through "pubs git"
* "pubs git" output without any "info:" prefix or extraneous new line.
* is_loaded() method for plugins
- git plugin now performs `git init`
- git call are checked
- only one git commit per pubs command
- SandboxedCommandTestCase for real hd usecase tests.
- `git --help` now documents `--config` and `--force-colors`
