Updated to newest Scala/Akka/Kryo versions.
Simplified the Eclipse install instructions with the new Typesafe IDE
Updated Travis CI version number.
Showcase for some performance/memory optimizations.

Runs in 2083 milliseconds on my puny laptop.
Edge count is correct, but 5000 vertices are missing compared to the
description. Is their vertex count correct?
Graph loading is not really optimized (memory tradeoff and I don't have
enough time to do better). Removed idle wait time, because its
description in the stats was misleading.
Pure Asynchrnous might perform better. Don't have the patience for a serious A/B test.
Better results without JVM parameter tuning.
Some comments and simplifications.
Using typed id/signal.

Should try to enable some specialization again.
Fixed bug in BulkMessageBus and added EffiecintSssp.

Need to clone the arrays or the signals/targetids or they will get
overwritten. We really ned to make this work with the default edges, so
we can test it more easily.
Using double slows things down only a little.

But it allows for higher precision and alleviates all concerns about
numerical problems.
Fixed comment on EfficientSssp.