explicitly require mock_class

Change-Id: I4dd332725c3fb9e544201083d59783a129bf03ab
Make frameworks and runtimes optional

- If framework is not specified use buildpack framework by default

- If runtime is not specified use ruby19 runtime by default
Update TODO in comments and rebase master
Merge branch 'optional-framework-runtime' of github.com:cloudfoundry/cloud_controller_ng into optional-framework-runtime

Conflicts:
	lib/cloud_controller/models/app.rb