Debug string in morph2
Rename a bad var name that led to troubles
Refactor plugin directive
Retrieve externalPlugins in MainController

Pretty ugly implementation...
Update plugin directive to handle external plugins
More explicitness in configuration
Retrieve more conf params in services
Use injector in MainController

We hold all services in arrays now to be more compatible with external
plugins that will most likely come as objects.
More partitioning is done, distinct listeners are passed to the state
service - not happy with that solution, have to think about this more.
Simplify plugin directive even more
Minor update of main2 template
Add skeleton for external history plugin
Add external history script to index
Handle listeners in state - more to come

Implementation of external listeners pending.
Extract external plugins container
Inline external history factory to an anonymous fn
No need to inject history into state anymore
WIP - external api