Add configurable processes plugin

We need to be able to get detailed statistics for processes and groups
of processes, so I have added a resource to configure the plugin.
Fix copy & paste error in README
Add test for plugin
Add an ensure parameter to remove conf file
Add spec test for processes plugin

I fixed a couple of things while building this:
  - processes.load was a copy paste hangover that I didn't like
  - Process in processes.conf.erb was indented with a tab = BAD
Merge pull request #53 from tombooth/add-processes-plugin

Add configurable processes plugin