vbv: lookahead
encoder: remember abort condition and stop accepting input frames
encoder: remove two completed TODOs
cleanup TEncSbac

--HG--
extra : source : e6d9fc837699175c1781ccb03d14b5f25f3cdc08
fix bug on TSKIP

--HG--
extra : source : eb71f4b6d0a6bdb796d51a3fb49af0e211dcbfcb
cli: use real log commands