Add ggregated global UI views and internal metrics

- Add a unified cluster view when running multiple stalker clusters.
  Closes #14
- Add statsd support to stalker-manager and stalker-runner to report
  internal metrics. Closes #15
Bump version
Add stats to global view
Why u nest so damn much!
Bump version
Add pagerduty incident key prefix option

Adds an option to add a custom prefix to the pager duty incident key.
Fix bug when grouping by host
Fix log line
Merge branch 'master' of github.com:pandemicsyn/stalker

Conflicts:
	stalker/__init__.py