Update Consul to v0.6.3

[matthewvalimaki]

See https://github.com/hashicorp/consul/blob/master/CHANGELOG.md and https://www.consul.io/docs/upgrade-specific.html.

Couple highlights important for us:

• TCP health check
• Sending telemetry (I see alpine-consul-statsd or similar coming)

Some breakage will happen:

• Data storage changes
• Web UI structure updated a bit

[smebberson]

@matthewvalimaki, sounds good. I'll work this in once we have #13 merged in.

[matthewvalimaki]

Related PRs: #28 and #29.

Note: since Consul 0.6.0 the AMD64 bin version works so no need to compile ourselves.

[smebberson]

PR #34 incorporates these changes. It's nice not having to build Consul anymore! Please note, I didn't make any changes regarding the UI yet, please see #30 regarding some questions on this.

Also, I didn't do anything specific regarding incompatibility. I think this should be handled downstream as needed.