Additional changes to processing of Num Lock on Android

Additional changes to processing of Num Lock on Android

* java/org/gnu/emacs/EmacsView.java (onKeyDown, onKeyMultiple)
(onKeyDown): Disregard Num and Scroll Lock keys, and return
value of window functions to the system.

* java/org/gnu/emacs/EmacsWindow.java (eventModifiers): Return
normalized meta state, not only those bits the system considers
modifiers.
(onKeyDown, onKeyUp): Ignore numpad keys to which no base
characters are assigned, so that the system may generate the
proper action keys instead.