ess parser: fix num_bits=64 case in get_bits()
ess parser: fix num_bits=64 case in get_bits()

kierank/bmxlib-bmx,ebu/ebu-bmx,stuarthicks/bmx,stuarthicks/bmx,Limecraft/ebu-bmx,stuarthicks/bmx,Limecraft/ebu-bmx,kierank/bmxlib-bmx,Limecraft/ebu-bmx,ebu/ebu-bmx,xunchangguo/BMX,kierank/bmxlib-bmx,ebu/ebu-bmx,xunchangguo/BMX,xunchangguo/BMX