Add meta-oe layer set to 'dylan' release branch.
Add necessary parts of meta-oe layer to bblayers for Xen.
Add meta-virtualization to LAYERS.

Had to fork and create an 'ndvm' branch to get meta-virtualization
to build against OE stuff from the 'dylan' release branches. I guess
meta-virtualization doesn't have any release branches.
Ignore meta-virtualization.
Ignore meta-intel.
Add meta-virtualization layer to bblayers.conf.
Increase priority of meta-hype layer.

This is to cause Xen recipe from meta-hype to be preferred over the
recipe from meta-virtualization.