Implement `yank-media' on Android

Implement `yank-media' on Android

* doc/emacs/android.texi (Android Windowing): Update selection
restrictions.
* java/org/gnu/emacs/EmacsClipboard.java (EmacsClipboard): New
functions `getClipboardTargets' and `getClipboardData'.
* java/org/gnu/emacs/EmacsSdk11Clipboard.java
(EmacsSdk11Clipboard, getClipboardTargets, getClipboardData):
Implement.
* java/org/gnu/emacs/EmacsSdk8Clipboard.java: Stub out new
functions.

* lisp/term/android-win.el (android-get-clipboard-1): Implement
MIME type targets.
* src/android.c (android_exception_check)
(android_exception_check_1, android_exception_check_2): Fix
punctuation in warning message.
(android_exception_check_nonnull_1): New function.
* src/android.h: Update prototypes.
* src/androidselect.c (struct android_emacs_clipboard): New
methods.
(android_init_emacs_clipboard): Initialize new methods.
(Fandroid_get_clipboard_targets, android_xfree_inside)
(Fandroid_get_clipboard_data): New functions.
(syms_of_androidselect): Define new subrs.