Updated Puppet::init to support specifying a runmode:
* Added a $runmode param which defaults to 'service'.
* Created paramater in init class. 
* Added a case statement to config class to include relevant class based
on runmode value.
Updated to use 'include' rather than 'class', as won't break existing
setups which have puppet and puppet::cron defined.
Ensure that using top-level variable for $::puppet::runmode.