fixed 2 possible heap overflows (inc. #1088)
GF_Err co64_Write(GF_Box *s, GF_BitStream *bs)
{
	GF_Err e;
	u32 i;
	GF_ChunkLargeOffsetBox *ptr = (GF_ChunkLargeOffsetBox *) s;

	e = gf_isom_full_box_write(s, bs);
	if (e) return e;
	gf_bs_write_u32(bs, ptr->nb_entries);
	for (i = 0; i < ptr->nb_entries; i++ ) {
		gf_bs_write_u64(bs, ptr->offsets[i]);
	}
	return GF_OK;
}

GF_Err co64_Write(GF_Box *s, GF_BitStream *bs)
{
	GF_Err e;
	u32 i;
	GF_ChunkLargeOffsetBox *ptr = (GF_ChunkLargeOffsetBox *) s;

	e = gf_isom_full_box_write(s, bs);
	if (e) return e;
	gf_bs_write_u32(bs, ptr->nb_entries);
	for (i = 0; i < ptr->nb_entries; i++ ) {
		gf_bs_write_u64(bs, ptr->offsets[i]);
	}
	return GF_OK;
}
