Remove unused variable that was moved & renamed elsewhere.

bin/Data/Scripts/Editor/EditorUI.as

@@ -56,7 +56,6 @@ bool uiFaded = false;
 float uiMinOpacity = 0.3;
 float uiMaxOpacity = 0.7;
 bool uiHidden = false;
-bool uiMmbPan = false;
 
 void CreateUI()
 {