MAJOR (WIP): Reorganized to enable 'config' and 'info' verbs

- Added `catkin config` verb
- Added `catkin info` verb
- Build configuration is now stored by the `config` verb
- Re-worked the `catkin clean` interface to be more intuitive
- Refactored many of the utility functions from `catkin build` to
  separate out their build-specific functionalities from functionalities
  which are useful for other verbs.
  - color.py
  - context.py
  - common.py
  - run*.py
- Moved resultspace-processing functions into resultspace.py