(svn r14679) -Fix [FS#2431]: opening the OSK on the chatbox did disable map scrolling (with keyboard) until another window with editbox was opened and closed. Just "refcount" the open edit boxes instead of setting/clearing a bit when opening/closing a window.

Makefile*
bin/*
bundle/*
!bin/data/chars.grf
!bin/data/openttdd.grf
!bin/data/openttdw.grf
!bin/data/opntitle.grf
!bin/scenario/README
!bin/scripts*
config.*
objs/*
src/rev.cpp