Rational arrays not read correctly

[sam6321]

https://github.com/geotiffjs/geotiff.js/blob/a2013a3790a657badade613169c9eaa1dc550a0b/src/geotiff.js#L161

When reading arrays of rational numbers (for example, when reading a GPSLatitude or GPSLongitude field) the reader does not index the output Uint32Array correctly, resulting in it skipping values on output.

A GPSLatitude array containing [71, 1, 25, 1, 47289959, 1000000] is currently being read as [71, 1, 47289959, 1000000, 0, 0]

The reading loop:

for (let i = 0; i < count; i += 2) {
  values[i] = readMethod.call(
    dataSlice, offset + (i * fieldTypeLength),
  );
  values[i + 1] = readMethod.call(
    dataSlice, offset + ((i * fieldTypeLength) + 4),
  );
}

Should instead be:

for (let i = 0; i < count; i++) {
  values[i * 2] = readMethod.call(
    dataSlice, offset + (i * fieldTypeLength),
  );
  values[i * 2 + 1] = readMethod.call(
    dataSlice, offset + ((i * fieldTypeLength) + 4),
  );
}