rename internal get/set functions

mainly because the salaam parser chokes on internal…

lib/parfait/layout.rb

@@ -74,8 +74,8 @@ module Parfait
       raise "Use variable_index instead"
     end
 
-    # index of the variable when using internal_object_get
-    # (internal_object_get is 1 based and 1 is always the layout)
+    # index of the variable when using get_internal
+    # (get_internal is 1 based and 1 is always the layout)
     def variable_index name
       has = super_index(name)
       return nil unless has