BUG: Add all special keys recognized by Qt.

We can support all of the special keys exposed by Qt by introspection. This does introduce some platform incompatibility for these extra characters, as they will not have the same names on wx (if they are eventually provided at all). Personally, I'm okay with that. If we do not provide these special keys at all, then the key event processing code will try to treat the enum integer value as a unicode character and fail.