Fixes golint errors in cmd/.
Fixes golint errors in pkg/api
Fixes golint errors in pkg/apiserver
Fixes golint errors in pkg/client
Fixes a syntax error of api/examples/service.json
Use docker client lib instead of binary for pulls
Add how to install deps
Merge pull request #373 from yugui/fix/examples

Fixes a syntax error of api/examples/service.json
Merge pull request #351 from discordianfish/use-api-for-pull

Use api for pulling images instead of shelling out
Merge pull request #372 from yugui/feature/golint

Fixes Go lint errors.
Add validation of VolumeMounts
Add validation of Ports

Also do caseless compares for "enum" strings.
Validation of HostPorts and Manifest IDs

Check that HostPorts are unique across the whole host and that Manifest IDs
are unique.