Enhancement: config command for the admin interface

Related: #360
Buffer incoming tcp data until we receive a complete metric
Initialise tcp buffer to empty string
Add crude test for input buffering on tcp server
Merge pull request #460 from benburry/tcp_server

Buffer incoming tcp data until we receive a complete metric
Add metrics_received counter

Similar to packets_received, but counts individual (good or bad) metrics lines
received
Merge pull request #461 from benburry/metric_count

Add metrics_received counter
Add documentation for server modules
Add server documentation links
Proxy with cluster module
Merge pull request #465 from falsecz/master

Proxy: add cluster module support to utilize all cpus for higher throughput
Merge pull request #384 from easybiblabs/topics/360_admin_config_command

Enhancement: config command for the admin interface
Merge pull request #4 from etsy/master

Pull in Upstream Changes