fixed 2 possible heap overflows (inc. #1088)
GF_Err stss_Size(GF_Box *s)
{
	GF_SyncSampleBox *ptr = (GF_SyncSampleBox *)s;
	ptr->size += 4 + (4 * ptr->nb_entries);
	return GF_OK;
}

GF_Err stss_Size(GF_Box *s)
{
	GF_SyncSampleBox *ptr = (GF_SyncSampleBox *)s;
	ptr->size += 4 + (4 * ptr->nb_entries);
	return GF_OK;
}
