Use correct OriginUpperLeft when linking more than one shader.

Semantics: Texture clamp functions are available for fragment shader only

Fix a CMakeLists issue

Fix build if NV_EXTENSIONS is not set

support SPV_NV_viewport_array2 and SPV_NV_stereo_view_rendering

Fix for not-handled-in-switch warnings

Added default to the switch() for AMD_EXTENSIONS to avoid a spew
of warning messages.

Fix compilation with MSVC 2010

HLSL: fix dereferencing when copying split structures with arrays

Implement SPV_KHR_subgroup_vote

SPV: Implement new revision of extension GL_AMD_shader_ballot

When copying split types with mixtures of user variables and buitins,
where the builtins are extracted, there is a parallel structures traversal.
The traversal was not obtaining the derefenced types in the array case.

- Add support for invocation functions with "InclusiveScan" and
  "ExclusiveScan" modes.
- Add support for invocation functions taking int64/uint64/doube/float16
  as inout data types.

doc.cpp: Add capabilities, scope to the opcodes. Add opcode and
capability strings.
GLSL.ext.KHR.h: Add extension
string.
GlslangToSpv.cpp: Fix handling of opcodes to generate
appropriate SPIR-V.
spirv.hpp: Add capability and opcode
enums.
spv.shaderGroupVote.comp.out: Update SPIR-V output for test
shader.

This reduces code duplication in a few ways, and better encapsulates
vector swizzle representation.

HLSL: Improved overload handling

Since EOpMatrixSwizzle is a new op, existing back-ends only work when the
front end first decomposes it to other operations. So far, this is only
being done for simple assignment into matrix swizzles.

This partially addressess issue #670, for when the matrix swizzle
degenerates to a component or column: m[c], m[c][r] (where HLSL
swaps rows and columns for user's view).

An error message is given for the arbitrary cases not covered.

These cases will work for arbitrary use of l-values.

Future work will handle more arbitrary swizzles, which might
not work as arbitrary l-values.

This encapsulates where the string could overflow, removing 40 lines
of fragile code.  It also improves handling of numbers that are too long.

There are a couple of open issues that could related to this function
being more rational (locale dependence, 1.#INF).

add other builtins to interstage IO

Includer interface change to support full include semantics (requires downstream changes)

Add a CMake option to disable compilation of HLSL input support.

Matches existing options.

(Still adding tests: do not commit)

This fixes PR #632 so that:

(a) The 4 PerVertex builtins are added to an interface block for all stages except fragment.

(b) Other builtin qualified variables are added as "loose" linkage members.

(c) Arrayness from the PerVertex builtins is moved to the PerVertex block.

(d) Sometimes, two PerVertex blocks are created, one for in, one for out (e.g, for some GS that
    both reads and writes a Position)

Address several compiler warnings

Reorder initializer fields to match variable declaration order (or vice versa) for several class constructors.