Issue 44: "const" is missing for const return types

The modifiers (things like const, volatile, etc) were not being added
to return types.
diff --git a/scripts/generator/cpp/gmock_class.py b/scripts/generator/cpp/gmock_class.py
index f2b3521..99a8965 100755
--- a/scripts/generator/cpp/gmock_class.py
+++ b/scripts/generator/cpp/gmock_class.py
@@ -54,7 +54,11 @@
         const = 'CONST_'
       return_type = 'void'
       if node.return_type:
-        return_type = node.return_type.name
+        # Add modifier bits like const.
+        modifiers = ''
+        if node.return_type.modifiers:
+          modifiers = ' '.join(node.return_type.modifiers) + ' '
+        return_type = modifiers + node.return_type.name
         if node.return_type.pointer:
           return_type += '*'
         if node.return_type.reference: