Fixes for OSX 10.9

This is a series of fixes to allow build the current master branch on OSX 10.9. It basically fixes one error and several warnings from the new clang compiler. 

Still some warnings that I don't know how to fix because the fix of it delivers one ambiguity compiling error between two members with the same signature. Curiously the warning is advertising that a virtual member is being hidden by the implementation in the derived class and only the number of parameter differences the implementation (the root class implementation has two parameters and the second one is optional and the inherited member implementation has only one -same- parameter)

Specifically there is one warning fix that takes my attention:

The compiler found a comparison statement in a non conditional statement:

warning: use of == instead of = on non conditional stament 

And the snippet of commit is this:
...
 		}
 		Gtk::TreeIter iter2(++iter);
 		if(!iter2)
-			iter==iter->parent();
+			iter=iter->parent();
 		else
...

Obviously there is one bug there because the iter variable is not changed inside the conditional statement. I hope this fixes the messages of non deleted value nodes after the program closes.