ElasticsearchAssertions.assertHitCount variants now report shard failure upon fail.

Cleaned up a UpdateNumberOfReplicasTests a bit.
removed a left over  assert made redundant by last commit
Delete API ack to wait also for actual deletion of shards from disk
closes #3413
auto_expand_replicas causing very large amount of cluster state changes when a node joins or leaves the cluster

Closes #3399
don't call the refresh mapping listener callback twice
though not harmful, results in an annoying transport service log
Forbid usage of StringReader in favor of FastStringReader.

StringReader is synchronized although input streams should always be consumed
by a single thread at a time. FastStringReader on the other hand is completely
thread unsafe.

Closes #3411