Issue #791 was partially fixed by PR #1161 (the mat mul implicit
truncations were its main point), but it still wouldn't compile due to
the use of ConstantBuffer as an identifier.  Apparently those fall into
the same class as "float float", where float is both a type and an
identifier.

This allows struct definitions with such keyword-identifiers,
and adds ConstantBuffer to the set.  'cbuffer int' is legal in HLSL,
and 'struct int' appears to only be rejected due to the redefinition
of the 'int' type.

Fixes #791

WIP: HLSL: matrix and vector truncations for m*v, v*m, m*m

HLSL truncates the vector, or one of the two matrix dimensions if there is a
dimensional mismatch in m*v, v*m, or m*m.

This PR adds that ability.  Conversion constructors are added as required.

Completes a TODO from previous commit.

Fixes #916 (the last change covered by the PR).
3rd list item in #976.

Fixes #1158.
Fixes #1159.

Addresses 2nd item in #976.

HLSL: Accept unorm and snorm on types

HLSL: ignore geometry attributes on non-GS stages.

If a shader includes a mixture of several stages, such as HS and GS,
the non-stage output geometry should be ignored, lest it conflict
with the stage output.

Memory fixes, round 1

Appveyor: avoid double testing on master commits

This is currently parsed and ignored, save for some minor validation.

Update README about the automatic master-tot relase

WIP: HLSL: implement TextureBuffer<type>

Make key objects using the memory pool own their own pool and delete it,
such that there is not generic per-thread pool to manage.

Addresses #928, #389, and 1st item in #976. Overlaps #916.

This had been dropped, when moving away from the old Win32 DLL model.

Issue: per-thread tear down for other threads.

Addresses step 4 of #976, overlaps #916.

For each pool, now, it is newed, remembered, and freed by the same entity,
rather than having a mix (thread finalize freeing current pool) that could
lead to double freeing of the same pool. It is quite rational and simple now.

This will enable reinstalling process and thread tear down.

This will make the next (functional) commit easier to see.

Update spirv-tools known good.

Travis: auto deploy build artifacts to GitHub Releases

Pushing a commit to the master branch will trigger a build on
Travis. If the build is successful, the artifacts will be
collected and pushed to GitHub Releases, under the "master-tot"
release.

Add script to crank test shaders through spirv-val

Reverse order of setShiftBindingForSet parameters

Appveyor: auto deploy build artifacts to GitHub Releases

Per feedback on PR #1111, this reverses the order of the parameters for the setShiftBinding API.

It is now:

    void TShader::setShiftBindingForSet(TResourceType res, unsigned int base, unsigned int set);

This script will crank a supplied set of glslang test shaders through the
spirv-val tool, reporting on the results.

There are some important things to note:

* Like 'runtests', this must be invoked from the 'Test' subdirectory.

* This is mostly useful on the hlsl.* tests, although it is not strictly
limited to those.  The reason is that most of the glsl tests either contain
validation error cases, and so fail to compile, or are not using a #version
compatible with producing SPIR-V modules.

* Some tests, such as negative tests, or most of the glsl tests, have
intentional compilation errors.  This script treats that as OK.  Failures
are successfully compiling shaders which proceed to fail spirv-val.

* spirv-val is looked for in either the External directory, or if not
found there, in a sibling directory of glslang, and if not found there
either, in /usr/local/bin.

* There are a bunch of command line options.  ./validate-shaders.sh --help
will describe them.

Some examples to try:

   ./validate-shaders.sh hlsl.*   # exercise all hlsl.* tests.
   ./validate-shaders.sh --terse hlsl.*  # same, but tersely.

   # dump validator results for problems in something.frag:
   ./validate-shaders.sh --quiet --dump-val something.frag

Pushing a commit to the master branch will trigger a build on
Appveyor. If the build is successful, the artifacts will be
collected and pushed to GitHub Releases, under the "master-tot"
release.

Almost equivalent to tbuffer, except members not at global scope.
So, reference is "TextureBuffer_var.member", not simply "member".