message: Also accept tab delimited PPM headers
diff: @@ -37,7 +37,7 @@ impl<R: Read> PPMDecoder<R> {
  let mut buffer: [u8;1] = [0];
  try!(reader.read_exact(&mut buffer));
  match buffer[0] {
  - b'\n' | b' ' | b'\r' => {
  + b'\n' | b' ' | b'\r' | b'\t' => {
  if bytes.len() > 0 {
  break // We're done as we already have some content
  }
  