Implement `fullscreen' on Android 4.0 and later

Implement `fullscreen' on Android 4.0 and later

* doc/emacs/android.texi (Android Windowing): Document what new
frame parameters are now supported.
* java/org/gnu/emacs/EmacsActivity.java (EmacsActivity): New
field `isFullscreen'.
(detachWindow, attachWindow): Sync fullscreen state.
(onWindowFocusChanged): Add more logging.
(onResume): Restore previous fullscreen state.
(syncFullscreen): New function.
* java/org/gnu/emacs/EmacsWindow.java (EmacsWindow)
(setFullscreen): New function.
* src/android.c (struct android_emacs_window): Add new method.
(android_init_emacs_window): Look up new method.
(android_set_fullscreen): New function.
* src/androidgui.h:
* src/androidterm.c (android_fullscreen_hook): Implement
accordingly.