message: Mat::to_vec_2d now properly converts non-continous Mats
diff: @@ -164,17 +164,29 @@ impl Mat {
  }
  let size = self.size()?;
  let width = size.width as usize;
  + if self.is_continuous()? {
  let data = self.data_typed()?;
  Ok((0..size.height)
  .map(|row_n| {
  let row_n = row_n as usize;
  let mut row = Vec::with_capacity(width);
  - unsafe { row.set_len(width); }
  - row[0..width].copy_from_slice(&data[row_n * width..(row_n + 1) * width]);
  + row.extend_from_slice(&data[row_n * width..(row_n + 1) * width]);
  row
  })
  .collect()
  )
  + } else {
  + Ok((0..size.height)
  + .map(|row_n| {
  + self.at_row(row_n).map(|src_row| {
  + let mut row = Vec::with_capacity(width);
  + row.extend_from_slice(src_row);
  + row
  + })
  + })
  + .collect::<Result<_>>()?
  + )
  + }
  })
  }
  }
  