updated generator for changes in the vk.xml spec
updated generator for changes in the vk.xml spec

 - we now put Handle property into IMarshalling and
   INonDispatchableHandleMarshalling interfaces to not clash with
   Handle field in structures

 - special case StructureType enum value for debug report, hopefuly
   that will be fixed in the spec

 - added set of known bitmasks as some of them in the Nv extension are
   missing type="bitmask"

mono/VulkanSharp