Document api types wrt validation

Part 3 in a series of changes towards data validation.
improvements to integration test organization
Improve logging.
Merge pull request #312 from thockin/valid4

Document api types wrt validation
Fixed the data race found in kubelet_test.go
Merge pull request #331 from dchen1107/cleanup

Fixed the data race found in kubelet_test.go
Merge pull request #326 from thockin/valid2

First piece ofn actual validation
Merge pull request #327 from lavalamp/etcdChanFix

Improvements to integration test & logging
Add validation of Volumes