First piece of validation

I'm adding pieces incrementally to make sure we get full testing of each
piece.

Make syncLoop() private
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
Replace the outdated cloudcfg.sh to kubecfg.sh

Replaces the outdated cloudcfg.sh to kubecfg.sh in the dynamic update demo.
Merge pull request #326 from thockin/valid2

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

Improvements to integration test & logging
Merge pull request #332 from thagikura/patch-1

Replace the outdated cloudcfg.sh to kubecfg.sh
Describe identifiers in Kubernetes

Documents #199
Add validation of Volumes
Merge pull request #329 from thockin/valid6

Add validation of Volumes
Change error printing for easier debugging
Fix interface{} in api/types.go; plumb through system.
Change kublet to serve podInfo instead of containerInfo. Plumb through system.
rearrange RunKubelet's parameters so that address and port are next to each other
Allow master's pod info getter to be faked. Wire up in integration tests in futile attempt to make travis pass.
Merge pull request #334 from smarterclayton/add_identifier_doc

Describe identifiers in Kubernetes