* Improve the ping endpoint so that it can optionally check for leader agreement across all meta servers
* Add Ping method to the meta client
* Fix ClusterID tests
* Remove WaitForLeader from meta client and remove unnecessary references to it
This ensures that the meta service will gracefully handle host name changes in a single server configuration.
It also changes the raft setup to use the user specified bind address (and thus hostname) instead of pulling it off the listener, which returns the IP. This will enable users to have hostnames listed instead of IPs in the megastore, making it easier to read. This also means that underlying IPs can change without causing problems in a cluster.
* increase sleep on error in client exec in case a server went down so we don't max out retries before a new leader gets elected
* update and add close logic to service, handler, raft state, and the client
* Add dir, hostname, and bind address to top level config since it applies to services other than meta
* Add enabled flags to example toml for data and meta services
* Wire up add/remove raft peers and meta servers to meta service
* Update DROP SERVER to be either DROP META SERVER or DROP DATA SERVER
* Bring over statement executor from old meta package
* Start meta service client implementation
* Update meta service test to use the client
* Wire up node ID/meta server storage information
David Norton
Paul Dix
Cory LaNou