Fix compatibility issues with Android clipboards

Fix compatibility issues with Android clipboards

* java/org/gnu/emacs/EmacsClipboard.java (getClipboardData):
Return an AssetFileDescriptor.

* java/org/gnu/emacs/EmacsContextMenu.java (onMenuItemClick):
Typo corrections in commentary.

* java/org/gnu/emacs/EmacsOpenActivity.java (onCreate): Raise
minimum version on which to read file descriptors from
ParcelFileDescriptor objects to Honeycomb.

* java/org/gnu/emacs/EmacsSdk11Clipboard.java
(getClipboardData): Return the asset file descriptor.

* java/org/gnu/emacs/EmacsSdk8Clipboard.java (getClipboardData):
Adjust return type to match.

* src/android.h (struct android_parcel_file_descriptor_class):
Move from androidselect.c.

* src/androidselect.c (fd_class): Export function.
(android_init_emacs_clipboard): Adjust signature of
getClipboardData.
(android_init_asset_file_descriptor, close_asset_fd)
(extract_fd_offsets): New functions.
(Fandroid_get_clipboard_data): Extract file descriptor and
offset from the AssetFileDescriptor here, rather than in
getClipboardData.
(init_androidselect): Call android_init_asset_file_descriptor.

* src/androidvfs.c (android_init_fd_class): Export and enable
calling this function more than once.