Conditional -> GUIObject and make all gui objects children of GUIObject

Signed-off-by: Vojtech Bocek <vbocek@gmail.com>

Change-Id: Ic0a7d6354dabe5919b83942f2f1aa0715625e522
diff --git a/gui/button.cpp b/gui/button.cpp
index b14e675..097bf71 100644
--- a/gui/button.cpp
+++ b/gui/button.cpp
@@ -43,7 +43,7 @@
 #include "objects.hpp"
 
 GUIButton::GUIButton(xml_node<>* node)
-	: Conditional(node)
+	: GUIObject(node)
 {
 	xml_attribute<>* attr;
 	xml_node<>* child;