README: mention git repos at xen.org

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
README: remove requirement for udev

There is no requirement for udev during package build. It may be
required at runtime even with libxl with run_hotplug_scripts=yes
in xl.conf.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Add INSTALL file

Document how to use configure and what to pass to make(1).

Signed-off-by: Olaf Hering <olaf@aepfle.de>
INSTALL

Signed-off-by: Olaf Hering <olaf@aepfle.de>