This uses ember-page-title to add dynamic page titles throughout the
route hierarchy. When there’s more than one region, the current
current region is added before the final entry of “- Nomad”.

api: return X-Nomad-Index header on allocation stop

nomad: include snapshot index when submitting plans

Collect driver stats when driver plugins are restarted

Avoid de-registering slowly restored services

take NodeID from url in api for node eligibility

Added line around interoperability to Downloads page.

The button shows a success icon and tooltip on click, and resets
after two seconds.

Updated the TensorRT demo to use the official NVIDIA image

Added Community task driver for FreeBSD jails

rpc: use tls wrapped connection for streaming rpc

This ensures that server-to-server streaming RPC calls use the tls
wrapped connections.

Prior to this, `streamingRpcImpl` function uses tls for setting header
and invoking the rpc method, but returns unwrapped tls connection.
Thus, streaming writes fail with tls errors.

This tls streaming bug existed since 0.8.0[1], but PR #5654[2]
exacerbated it in 0.9.2.  Prior to PR #5654, nomad client used to
shuffle servers at every heartbeat -- `servers.Manager.setServers`[3]
always shuffled servers and was called by heartbeat code[4].  Shuffling
servers meant that a nomad client would heartbeat and establish a
connection against all nomad servers eventually.  When handling
streaming RPC calls, nomad servers used these local connection to
communicate directly to the client.  The server-to-server forwarding
logic was left mostly unexercised.

PR #5654 means that a nomad client may connect to a single server only
and caused the server-to-server forward streaming RPC code to get
exercised more and unearthed the problem.

[1] https://github.com/hashicorp/nomad/blob/v0.8.0/nomad/rpc.go#L501-L515
[2] https://github.com/hashicorp/nomad/pull/5654
[3] https://github.com/hashicorp/nomad/blob/v0.9.1/client/servers/manager.go#L198-L216
[4] https://github.com/hashicorp/nomad/blob/v0.9.1/client/client.go#L1603

* enable vault, consul, and nomad services to make them persistent after reboot

* update AMI

systemd: set a high but non-infinite fd limit

Previously, if a channel is closed, we retry the Stats call.  But, if that call
fails, we go in a backoff loop without calling Stats ever again.

Here, we use a utility function for calling driverHandle.Stats call that retries
as one expects.

I aimed to preserve the logging formats but made small improvements as I saw fit.

The driver plugin stub client must call `grpcutils.HandleGrpcErr` to handle plugin
shutdown similar to other functions.  This ensures that TaskStats returns
`ErrPluginShutdown` when plugin shutdown.

batch node deregistration