Update Android port

Update Android port

* java/org/gnu/emacs/EmacsInputConnection.java
(requestCursorUpdates):
* java/org/gnu/emacs/EmacsNative.java (requestCursorUpdates):
* java/org/gnu/emacs/EmacsService.java (updateCursorAnchorInfo):
New functions.
* src/android.c (struct android_emacs_service)
(android_init_emacs_service): Add new method.
(android_update_cursor_anchor_info): New function.
* src/androidfns.c (android_set_preeditarea): New function.
* src/androidgui.h (enum android_ime_operation): New operation
`REQUEST_CURSOR_UPDATES'.
(struct android_ime_event): Document new meaning of `length'.
* src/androidterm.c (android_request_cursor_updates): New
function.
(android_handle_ime_event): Handle new operations.
(handle_one_android_event, android_draw_window_cursor): Update
the preedit area if needed, like on X.
(requestCursorUpdates): New function.
* src/androidterm.h (struct android_output): New field
`need_cursor_updates'.