Merge pull request #57 from tmatsuo/master

Fixed nil pointer dereference error when the Message == nil
Introduce a Context type.
Fix minor lint error.
Merge branch 'master' of github.com:GoogleCloudPlatform/gcloud-golang
Fixing the broken build.
Remove storage.Client, use a context, flatten the storage package.
Delete the empty test file.
Handle 404 for the raw request.
Adding a TODO to initiate the service objects lazily.