Update doc files for initial policyfile release
Cleanup TODOs that have been addressed or scheduled for later
Move UI out of Command namespace

UI is generally 'command' related, but is integrated deeply into library
code now (defaulting to "null" ui).
rm TODOs for path de-duplication.

Kicking this can down the road.
Add tests for install command
Add tests for `push` command
TEMPORARY - use chef from git to get WorkstationConfigLoader
Remove uneeded memoization