Fix several build warnings/error encountered with VS2013

SPIRV/GlslangToSpv.cpp

@@ -2954,7 +2954,7 @@ spv::Id TGlslangToSpvTraverser::createMiscOperation(glslang::TOperator op, spv::
 
     spv::Op opCode = spv::OpNop;
     int libCall = -1;
-    int consumedOperands = operands.size();
+    size_t consumedOperands = operands.size();
     spv::Id typeId0 = 0;
     if (consumedOperands > 0)
         typeId0 = builder.getTypeId(operands[0]);

SPIRV/SpvBuilder.cpp

@@ -1365,7 +1365,7 @@ Id Builder::createTextureQueryCall(Op opCode, const TextureParameters& parameter
     case OpImageQuerySize:
     case OpImageQuerySizeLod:
     {
-        int numComponents;
+        int numComponents = 0;
         switch (getTypeDimensionality(getImageType(parameters.sampler))) {
         case Dim1D:
         case DimBuffer:

glslang/MachineIndependent/Scan.cpp

@@ -309,7 +309,7 @@ struct str_hash
         unsigned long hash = 5381;
         int c;
 
-        while ((c = *str++))
+        while ((c = *str++) != 0)
             hash = ((hash << 5) + hash) + c;
 
         return hash;