additional key events

Hello everybody,

sometimes I need more than the available key events -
e.g. 'enter', 'backspace' or the keys from numeric keypad.
That's why I tried to include more events in the backends (backend_wx.py,
backend_tkagg.py, backend_gtk.py).
I tested it on a debian etch (Python 2.4.4, wxpython 2.6.3.2).

Attached is a patch to svn.
Maybe some expert could have a look over this and, if suitable, include it in
matplotlib.

I don't know much about backends. That's why some problems remained:
TkAgg: No difference in behaviour if Num Lock is locked or not (you always get
the number characters).
Gtk : With NumLock locked the keys give 'None'. With NumLock unlocked the
number characters occur in my program, but the PC uses the arrow keys, too.
Therefore you switch to the mpl-figure-toolbar and the keys don't work
anymore.

best regards,
Matthias

key_event_add.patch (6.2 KB)