Fix several build warnings/error encountered with VS2013

This also fixes the newlines for spirv.hpp to be consistent with the rest of the files.

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;