Remove obsolete zk Docker example.

The useful parts of the zk Docker example have been absorbed into the
Kubernetes example. The Docker-only version is now broken anyway and
there's no point in fixing it since we're not planning to flesh out the
rest of Vitess in Docker-only mode.
Add GetSrvKeyspaceNames command to vtctl.
Allow tablet hostname to be overridden.

Kubernetes sets a hostname for each pod that can't be changed
dynamically, and can't be resolved by other pods. We need to tell
vttablet to report its hostname in the topology as something
globally resolvable (or as a fixed IP), instead of asking the OS.
Add DataTypes integration test to Java client
Merge pull request #126 from youtube/vitess-java

Add DataTypes integration test to Java client
Fix update stream test. Update Stream RPC service now runs on masters too.
Merge branch 'master' of github.com:youtube/vitess
Java client: Add IntegrityException
Merge pull request #124 from youtube/replication

Replication
Merge pull request #127 from youtube/vitess-java

Java client: Add IntegrityException
Adding topo helper methods SourceShardDelete and SourceShardAdd
for emergency hacking of the SourceShard objects.
Merge branch 'master' into resharding
GetSrvKeyspaceNames command test
Merge pull request #129 from qfel/vtctl_keyspace_names

Add GetSrvKeyspaceNames command to vtctl.
Merge pull request #125 from youtube/docker

Allow tablet hostname to be overridden.
Merge pull request #130 from youtube/resharding

Resharding