movdump: allow isom name > 255 chars and avoid VS8 conversion warning
movdump: allow isom name > 255 chars and avoid VS8 conversion warning

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