Added Mathias Ettinger to AUTHORS.
Added Mathias Ettinger to AUTHORS.

syaiful6/cartridge,wyzex/cartridge,syaiful6/cartridge,stephenmcd/cartridge,ryneeverett/cartridge,traxxas/cartridge,wbtuomela/cartridge,dsanders11/cartridge,wbtuomela/cartridge,Parisson/cartridge,wyzex/cartridge,Parisson/cartridge,traxxas/cartridge,dsanders11/cartridge,wyzex/cartridge,stephenmcd/cartridge,ryneeverett/cartridge,ryneeverett/cartridge,syaiful6/cartridge,stephenmcd/cartridge,dsanders11/cartridge,traxxas/cartridge,Parisson/cartridge,wbtuomela/cartridge