Remove vim modeline

It doesn't work because of the `:` in `cinoptions`, so forget the whole
thing.

Instead I recommend this in your vimrc(5):

    set cinoptions=:0,t0,+4,(4
    au BufNewFile,BufReadPost *.c setl noet sw=0 ts=8
    au BufNewFile,BufReadPost *.h setl noet sw=0 ts=8

(I bet there's a way to merge those last two lines.)