New :cloneFull() method on all objects, this makes a perfect clone of the...

New :cloneFull() method on all objects, this makes a perfect clone of the given object and any subjects recursively without creting duplicates of subobjects. This is nearly instantaneous and thus could be used to create time travel spells and other neat things.
Saves can now be made in the background while continuing to play the game. This obviously speeds ups considerably the gameplay since saves now "feel" instant.
*WARNING* Module makers: I had to change how savefiles work, there is a few changes needed in your modules for it to work.
 * In Game.lua: change the Savefile code in saveGame() to be just a call to savefile_pipe:push(game.save_name, "game", game)
 * In dialogs.Death too
 * Take a look at either the example module or ToME to see how it works exactly, it's really easy to convert


git-svn-id: http://svn.net-core.org/repos/t-engine4@1119 51575b47-30f0-44d4-a5cc-537603b46e54