Add support for base ClearCase

[praqma-thi]

I took the previous pull request and nuked most of the history on it. Took out most of the changes to the build.gradle and started cleaning up a bit.

• [X] Add skeleton to help Johnny implement the actual support
• [X] Implement and fleshen out support for base ClearCase
• [X] Clean up history
• [x] Add JavaDoc to added classes/methods
• [ ] Write tests to verify the contexts are working as expected
• [x] Add entries to the docs for base ClearCase
• [x] Clean up the code some more

[praqma-thi]

I'll be accepting this as I'm still figuring out how to properly test the contexts without running the prepare and cleanups during the tests