Reduced index size.

- Index vertex does not store the entire id of its child vertices
anymore, but only the delta.
- Optimizing the edge representation after graph loading by
transforming them from a list to an array.
- Removed triple vertices and replaced look-ups with binary search on
the third index level, now called BindingIndexVertex.
- Using CompactIntSet to further reduce the index sizes on levels 1 and
2.
Using the ParallelBulkMessageBus.
Added cardinalities to all index vertices.
The query is now sent into the index from the query vertex.

Much better performance combined with the current signal-collect core
version (1a27ffb195). Yey!
Changed cardinality request/reply protocol.
Query vertex gathers the pattern cardinalities before dispatching the query.
The query vertex can now optionally reorder the triple patterns by ascending cardinalities.
Fixed LubmBenchmark
Added additional heuristic to query optimizer.
Query planner can be selected when executing a query. Default is Greedy.
Switched to the old MessageBus, implemented different jar name, option for smaller LUBM load.
Fixed file lowding for Lubm limited option.