Fix support for olinuxino-a13 board.
Install fex file for mele board.
Simplify IMAGE_DEPENDS of a10-sdimg class, install fex file wathever the board selected.
Rename a10-sdimg with sunxi-sdimg
Factorise sunxi machines definition
Change filename for sunxi-img class to match the new one.
Add emac driver for cubieboard and try to load it at startup