Merge pull request #37 from brian-brazil/master

Remove decrement from counter.
Merge pull request #38 from brian-brazil/master

Add increment/decrement methods to Gauge.
avoid blocking on partials creation
Merge pull request #40 from fwbrasil/avoid-blocking

avoid blocking on partials creation
Initial version of new java client for prometheus.

This is based on the existing client, with the following changes:
 - No external dependencies in core client
 - Number of labels is fixed
 - Initilises to 0 when there's no labels
 - Convenience methods for no labels
 - Support for multiple registries
 - Only supports text output format

This code is MVP, there's no validation of metric or label names,
AtomicDouble might be better in Counter/Gauge and I'm sure there's a better
way to architect all this class wise (the api is a bit text format specific
for Summary for example).
Merge pull request #41 from brian-brazil/clientng

Initial version of new java client for prometheus.
Add pushgateway support to the simpleclient.

Refactor production of the text format into a separate module.
Merge pull request #42 from brian-brazil/pushgateway

Add pushgateway support to the simpleclient.