it is not anymore necessary to add an empty source to purge directories
new style for 2.7
new style for 2.7
refactor things for >2.7
remove hiera
take hiera out of the params
we don't need to remove the munin stuff when disabling
add a way to manage exim as default mta
make it work on 2.6
only do that on systems that require it to do
only set it to the default mta if it actually works