Division-by-zero fix in RoundRobinLoadBalancerFactory when no nodes with right capability is online

Old code would send down empty list to chooseNext, which would do '% items.size', triggering ArithmeticException(/ by zero)
Test included
Java-compat, make sure java-nodes are capabilities aware
Java-network: add sendRequest calls which are capabilities & maxRetry-aware.
Merge pull request #37 from stromnet/java-improvements

Misc fixes and improvements