1.3 Xen Improvements

A large number of bug fixes and security fixes have been backported for this release to include the features available in Xen 4.3.

A fix has been applied to the Xen pciback driver to allow it to take control of devices and to prevent native drivers from loading. This change makes it easier for developers to do PCI passthrough. The driver has also been compiled directly into the kernel and does not require a separate module.