Move Docker examples to top-level examples dir.
Add Dockerfile for vitess/root image.
First pass at Kubernetes support.
Add Kubernetes config for vtctld.
Fixed KeyRange object and associated references.
tabletserver: move taks.Wait to Close.

There's a subtle race condition. Queries that are currently
executing can launch new tasks after WaitForTxEmpty has
returned. So, the tasks.Wait should only be done after
all existing queries have completed, by which time no new
tasks will be launched.
Merge branch 'suguwork'