Minor changes to GoL
Last crazy breaking change:

- Simplified the signal/collect function signatures
- Removed unnecessary type parameter from TopKFinder
- Removed DSAN & Constraints
- Demoted "vertex with this id exists already" message from warning to
debug
Fixed Clustering Coefficient Algorithm
Replaced Java HashMap with Scala OpenHashMap inside Vertex Implementations
Added Java Map Vertex Storage and Tests

Fixes issue #60
Termination conditions are now returned in the right order of priority

Convergence is more important than reaching a time limit.
Bulk message bus now supports source ids