Implement SPV_KHR_subgroup_vote

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.

SPIRV/spirv.hpp

@@ -605,6 +605,7 @@ enum Capability {
     CapabilityMultiViewport = 57,
     CapabilitySubgroupBallotKHR = 4423,
     CapabilityDrawParameters = 4427,
+    CapabilitySubgroupVoteKHR = 4431,
     CapabilityMax = 0x7fffffff,
 };
 
@@ -906,6 +907,9 @@ enum Op {
     OpSubgroupBallotKHR = 4421,
     OpSubgroupFirstInvocationKHR = 4422,
     OpSubgroupReadInvocationKHR = 4432,
+    OpSubgroupAllKHR = 4428,
+    OpSubgroupAnyKHR = 4429,
+    OpSubgroupAllEqualKHR = 4430,
     OpMax = 0x7fffffff,
 };