Removed cast to Long

This prevents situations where Mongo returns numeric values as an int, instead
of the long Axon requires.

Issues #AXON-97 Fixed
Added random value to cluster name in test for concurrent builds

Concurrent builds would interfere because they use the same cluster name,
making Jgroups see all components started in different tests as a cluster.
Merge branch 'master' of https://github.com/AxonFramework/AxonFramework