feature #1163: change xen4 drivers to use xl instead of xm
feature #1163: add support for hvm in xen4 drivers
feature #1163: use image format as prefix for disks
feature #1163: XenDriver modifications to handle drivers with and without ':' and include support for HVM
feature #1163: get domain name from deployment file in xen4 deploy
feature #1163: merge xen3 and xen4 drivers, added parameters in xenrc
feature #1163: split im drivers for xen3 and xen4
Merge branch 'feature-1163'