When using Astyanax from Scala, we cannot depend on the SystemClassLoader
being well-defined.  I was unable to run tests due to an issue
with astyanax-entity-mapper:test; however, astyanax-cassandra tests did seem to pass.
Merge pull request #315 from splittingfield/fix_class_loader_for_embedded_cassandra

Change EmbeddedCassandra to NOT use system class loader
Rename MessageQueueSettings to MessageQueueMetadata and deprecate
client config such as polling interval, which doesn't belong here.
Improved API for specifying a custom shard reading policy.
Update default retry delay to 10 seconds, 1 second was too aggressive
Minor cleanup
Expose the shard reader policy
Merge pull request #316 from elandau/queue

Rename MessageQueueSettings to MessageQueueMetadata and deprecate