Prior to this refactor, certain options would cause the game list to refresh when the config modal dialog is closed (such as adding a folder to the path list). This restores that functionality.
Prior to this, ConfigMain.cpp was a large (52KB) cpp file that contained all of the UI setting code.
This breaks up the config code into subclasses of wxPanel, which are then just instantiated to add to the settings wxNoteBook. This keeps all the settings categories separated from one another and also cleans up the code in general.
