Fix collector crash from long-running plugins
Added multithreading support to "active check" plugins
Version bump and changelog update
Merge branch 'master' into feature/collector-plugin-improvements

Conflicts:
	monagent/collector/checks_d/http_check.py
Removed 'Monasca' references
Fixing bug in token handling.  Removing /tokens from keystone URL
Fixing bug in token handling.  Removing /tokens from keystone URL
Merge pull request #15 from hpcloud-mon/feature/collector-plugin-improvements

Feature/collector plugin improvements