Sp6.sc3.api consistency

Updated API to follow the guidelines set in issue #83 
if a resource does not exist when a specific ID is asked for, a 404 is generated.
If a call to list all the resources of a specific type for example localhost/user/1/resources/1/streams , 
a JSON-object with the pattern {<resource_type>: [<list of objects>]}
In the above example, the object {"streams": []} would be returned if there were no streams belonging to resource with ID 1