Client for playing 300 publicly available Sokoban puzzles on a computer or phone.
one_time_save = function()
	print('saving to '..Current_pane.filename)
	local dir = Current_pane.is_stash and Stash_directory or Directory
	Current_pane.editor_state.filename = dir..Current_pane.filename
	save_to_disk(Current_pane.editor_state)
	-- Don't autosave yet; undo isn't accessible in mobile devices.
	Current_pane.editor_state.filename = nil
end