some problems with vPopupMenu

["Jonathan B. Hacker" <jbh@risc.rockwell.com>]

I've run into the following minor issues with the new vPopupMenu class.

1) in popmenu.h VMENU_H conflicts with the variable of the same 
name in menu.h.  I changed it to VPOPMENU_H

2) in popmenu.h MAX_MENU_BUTTONS conflicts with the variable of
the same name in menu.h.  I changed it to MAX_POPMENU_BUTTONS


Regards,
Jon Hacker