Install CM plugins
Implement YARN roles
Implement Spark roles
Resolve Debian derived distro install issues when CM version absolutely specified
Ensure yum install exclude jdk is observed  via retry helpers
Add manual steps to ensure Oozie web ui works out of the box
Set Oozie world permissions, given init ocurs pre user create
Add pre/post CDH parcel install configure scripts
Enable YARN roles for CDH4
Download YARN configs on CDH4
Merge pull request #49 from ggear/graham-patch-CDH-15652

CDH-15652: Whirr-CM to support Spark