Implemented type args in config schema

Added 'enum' and 'regex' types
Update ConfigSchema to support iteration, len and getitem
Added ProcessResource to model
Implemented permission saving for FileResources
Added new base class for all model resources
Renamed Host model to HostResource
Added DirectoryResource; implemented discovery for files and directories
Needed for blueprint:
https://blueprints.launchpad.net/rubick/+spec/python33-support

Change-Id: I41f67db38ee3894aa8cf3d6e51991b027dc20485