Add API documentation pre-commit hook.
fix link to skydns docs
Clarify spec vs status, and what we plan to do with usage.
Merge pull request #2500 from skelterjohn/patch-1

fix link to skydns docs
Cleanup
Merge pull request #2482 from bgrant0607/doctest

Add API documentation pre-commit hook.
Merge pull request #2480 from bgrant0607/docfix

Clarify spec vs status, and what we plan to do with usage.