Add CrowbarPacemakerHelper.is_cluster_founder? helper

This will avoid other cookbooks having to know about implementation
details for determining if a node is a founder or not.
Add CrowbarPacemakerHelper.cluster_founder helper

This will avoid other cookbooks having to know about implementation
details for finding the founder.
Merge pull request #52 from vuntz/is-founder

Add helpers to hide implementation details for other cookbooks
outdated-wfc-timeout has to be shorter than degr-wfc-timeout
fix output format from drbd-overview command
include proper recipe resource in default.rb
run resource directory
add mount condition
disable DRBD's online usage counter
add :immediate to subscriptions
wait for drbd resource
remove unnecessary ruby_block
allow to create multi resources
change how default.rb is included