Optionally omit stats_counts metrics

Adds the 'flush_counts' config. Defaults to true, so existing configs
aren't affected.
refactor stat deletion code, no functional changes
delete all metrics in a folder using a command like: delcounters path.to.parent.*
delete stats via management console: move to lib/, docs, generalize, tests
Add health status functionality
adding SIGTERM handling
initial proxy P.O.C.
Add hashring as optional dependency
Cleanup shutdown process
Don't need to test on .9 now that .10 is out.

We'll stick to supporting stable branches of node for now, and test on future unstable when they are close to being released as stable.
Merge pull request #280 from etsy/health_status

Add health status functionality, and handle SIGTERM more gracefully.
Update to use config library, make cacheSize a config option, and switch to using the health status
Add local config to git ignore
Remove statsCached from console backend
Revert "Add local config to git ignore"

This reverts commit 61fb8a096b2c26fcec40bf4feed77ae8f9817703.
Merge pull request #289 from bmhatfield/fix-console

Remove caching from the console backend
Merge pull request #246 from carver/delete-group

Delete folder of metrics with: delcounters parent.path.*
Update docs to include del* commands

Updated command list to show all the delete commands, as well as adding an example to show how to delete a folder of counters.
Add link to statsd-http-backend
Merge pull request #291 from bmhatfield/http-backend-link

Add link to statsd-http-backend