Update kombu to version 3.0.12

This is required due the celery upgrade in the last commit.
models.py: Slice, Segment and Block
Correct formating issues in models module
blockwisesopnet: control code for block wise sopnet models
Testing SOPNET control code
Remove unneeded pass statements
Add infrastructure to move sopnet code in own package
Move Sopnet code to own application
Djsopnet: Add basic migrations
Djsopnet: add basic admin views for models
Add Celery-sopnet dependency for djsopnet
Djsopnet: add sample code for celery-sopnet inegration
Djsopnet: simplify URL interface further

The 'sopnet/' part isn't needed anymore, now that Djsopnet is an own Django
application.
Djsopnet: add bootstrap and angular libs for test page
Let django know about the celery-sopnet tasks
Djsopnet: add basic AngularJS overview page
Make celerysopnet dependency a non-development dependency
Simplify Djsopnet URLs even more
Adjust formatting of Djsopnet URL configuration
Added explicit Assembly class to Djsopnet that express different types of assemblies