Add APIObject for generic inclusion of API objects.

Includes test and json/yaml getters and setters.
clean up code comments for the kubecfg command

This patch removes unnecessary code comments and improves the comment
for the readConfig function.
remove unnecessary expectNoError helper function

This patch completes a TODO item for the replication_controller test
suite by removing the expectNoError helper function, which does not
reduce enough typing to justify its usage.
If no tag was specified, pull "latest" explicitly.

When no tag is given to Docker pull, it downloads all tags. This could be a
significantly large number of images and in the end we only ever run
:latest.
Merge pull request #537 from kelseyhightower/kubecfg_comments

clean up code comments for the kubecfg command
Merge pull request #540 from vmarmol/always-latest

If no tag was specified, pull "latest" explicitly.
Merge pull request #529 from lavalamp/recursiveApiObj

Add APIObject for generic inclusion of API objects
add tests for the httplog package

Currently there are no tests for the httplog package. This patch adds
an initial set of tests and improves test coverage.
use %v instead of %#v when logging failures
add tests for the healthz package

Currently there are no tests for the healthz package. This patch adds
an initial set of tests and improves test coverage.
Merge pull request #542 from kelseyhightower/heathz_tests

add tests for the healthz package
Merge pull request #541 from kelseyhightower/httplog_test

add tests for the httplog package
Remove unnecessary expectNoError helper function

This patch completes a TODO item for the kubecfg package test suite by
removing the expectNoError helper function, which does not reduce enough
typing to justify its usage.
Add test cases for Docker image name parsing and cleanup

The tests for Docker image name parsing are repetitive and do not
cover enough test cases.

Refactor the tests to use table testing and add additional test cases.
Merge pull request #546 from kelseyhightower/kubecfg_tests

Remove unnecessary expectNoError helper function
Merge pull request #547 from kelseyhightower/kubelet_tests

Add test cases for Docker image name parsing and cleanup
Merge pull request #538 from kelseyhightower/replication_controller_test

remove unnecessary expectNoError helper function
Refactor Kubelet config sources for clarity

Create a new "Pod" concept which can identify pods from
many config sources.
Switch the Kubelet to use kubelet/config

Also transfer the Kubelet from using ContainerManifest.ID to source specific
identifiers with namespacing.  Move goroutine behavior out of kubelet/ and
into integration.go and cmd/kubelet/kubelet.go for better isolation.