Optionally omit stats_counts metrics

Adds the 'flush_counts' config. Defaults to true, so existing configs
aren't affected.
Allow for setting the process wtitle, or opting to let the os do it like previous versions
exclude the title test from running on Macs running node less than 10
note the fact that it won't work on node v0.8 on macs in the example config
Merge branch 'master' into optional_counts

Fixed merge conflict for new & legacy namespaces

Conflicts:
	backends/graphite.js
Merge pull request #148 from ktheory/optional_counts

Optionally omit stats_counts metrics
Merge pull request #311 from etsy/process_mgmt

Allow for setting the process title