Memory: Don't use pool memory to store the entry point name in the intermediate representation.

This might address issue #221, which I couldn't reproduce.
diff --git a/SPIRV/GlslangToSpv.cpp b/SPIRV/GlslangToSpv.cpp
index 6a86e21..8dfc681 100755
--- a/SPIRV/GlslangToSpv.cpp
+++ b/SPIRV/GlslangToSpv.cpp
@@ -2126,7 +2126,7 @@
 {
     // have to ignore mangling and just look at the base name
     int firstOpen = node->getName().find('(');
-    return node->getName().compare(0, firstOpen, glslangIntermediate->getEntryPoint()) == 0;
+    return node->getName().compare(0, firstOpen, glslangIntermediate->getEntryPoint().c_str()) == 0;
 }
 
 // Make all the functions, skeletally, without actually visiting their bodies.