Work in progress: import autorestart into dogstatsd

Move AgentSupervisor to Daemon.
Plus a number of other pylint fixes.
Merge branch 'master' into dogstatsd-autorestart
Merge branch 'master' into dogstatsd-autorestart
Initial tests for autorestart
Merge branch 'master' into dogstatsd-autorestart
Add `make lint`
Move lint task to Rakefile :unamused:
pylint is now required to develop dd-agent
Indentation error
Completely terminate dogstatsd when autorestart is enabled
Do not hard-code parent class in Dogstatsd.stop()
Update MySQL logging to use correct level for errors/exceptions.
Fix warning formatting so it can support multi-line messages.
Merge pull request #625 from DataDog/warning_traceback

Update MySQL error levels, allow multi-line messages with `self.warning`.
Specify default port in mcache config
Remove extraneous imports
Fix AgentSupervisor when watchdog kills child process
Update Daemon stop to kill process group
Fix Platform typo.
Merge branch 'limit-devices'