Redo Game List with generic popup

Check in ngamelist.c
Redo Game List with generic popup
 The X-independent code (i.e. almost all) is moved to a new file
 ngamelist.c.
Make button in Game List to pop up Game List Options
Fix scrolling game list
Fix popup of existing Game List after loading file
Wheel-scroll game list
Symbolic reference game list
TopLevel game list
Put format flags with listbox options