Change save param

Change the save parameter for call operation methods to be defined by the name of the target pin since this is independent from the operation definition.

Add unit test to validate that a class method can be assigned to different temporary variables.

Return parameter comments for activity diagram methods were not being printed as expected.

Add some structural comments to activity.mtl.

Jenkins test results: https://76.230.136.103:8085/job/temp_project/56/testReport/