Add lsmash_bs_is_error().
Add lsmash_bs_is_error().

Signed-off-by: Derek Buitenhuis <aff7d637ede26ea82e5226e01b697996cc52e526@gmail.com>

maki-rxrz/L-SMASH,canbal/l-smash,maki-rxrz/L-SMASH,silverfilain/L-SMASH,silverfilain/L-SMASH,canbal/l-smash,silverfilain/L-SMASH,l-smash/l-smash,l-smash/l-smash,l-smash/l-smash