Fix window.addch() of the curses module for special characters like
curses.ACS_HLINE: the Python function addch(int) and addch(bytes) is now
calling the C function waddch()/mvwaddch() (as it was done in Python 3.2),
instead of wadd_wch()/mvwadd_wch(). The Python function addch(str) is still
calling the C function wadd_wch()/mvwadd_wch() if the Python curses is linked
to libncursesw.