Merge pull request #1 from google/master

sync upstream
planb_check and a sample LaundDaemon plist

planb_check verifies the last successful run date of your management tools, and triggers a planb run if it's been too long.
Add description of planb_check to README.md
Merge pull request #1 from ccaviness/master

Add an example planb_check script and launchd config file