fixed 2 possible heap overflows (inc. #1088)
GF_Err def_cont_box_Write(GF_Box *s, GF_BitStream *bs)
{
	return gf_isom_box_write_header(s, bs);
}

GF_Err def_cont_box_Write(GF_Box *s, GF_BitStream *bs)
{
	return gf_isom_box_write_header(s, bs);
}
