Solves reloading of tree problem by loading tree structure open
merged auditlog from studentView
not done
merged session time management
still working with the remove students interface
Completed audit log front end
merged aggregators backend with dummy frontend

Best of and simple sum complete
Merge branch 'develop' into Aggregation

Conflicts:
	hamster_marking_system/business_logic/admin.py
	hamster_marking_system/business_logic/api.py
	hamster_marking_system/business_logic/models.py
	hamster_marking_system/hamster/urls.py
	hamster_marking_system/web_interface/templates/web_interface/testing.htm
	hamster_marking_system/web_interface/views.py
	hamster_marking_system/web_services/views.py
catering for weighted sum aggregation