Apply rave.missing as default overrides from all rave extensions.

Stop expecting moduleType to be an array.
Stop supplying a moduleType array, so it can be provided if missing/undefined.
Apply overrides from third-party packages and missing defaults from the application metadata.

Add debug messages for each override/missing.
Merge pull request #49 from RaveJS/missing

Apply rave.missing as default overrides from all rave extensions. See #43.