This extension adds the revision field to the
XML tag for extensions. This allows a version
macro to be generated with:

* KhronosGroup/OpenCL-Headers#251
* KhronosGroup/OpenCL-Headers#248

KHR extensions are given a revision based on the semantic
version of the spec. However other extensions don't use
semantic versioning, and so are given a placeholder `0.0.0`
value until they can be updated by the owner.

The XML schema is also updated to make the revision field
mandatory in the XML entry for extensions and the
existence of the macro this enables is advertised to users
in the spec.

Links were not created for commands defined by extensions. With this
changes all uses of e.g. {clCreateSemaphoreWithPropertiesKHR} link
to the definition of the command which makes navigating the specification
much easier.


Change-Id: I4a9458609f4ba3229b66e3d169a68cb4564e2538

Signed-off-by: Kevin Petit <kevin.petit@arm.com>

Update  external_memory_win32_name_handle with latest
updates from main.

Bump up spec versions for
cl_khr_external_memory_win32 from 1.0.0 to 1.1.0
and cl_khr_external_semaphore_win32 from 0.9.0 to 0.9.1