Output dtype

[dy]

Would be nice to provide various output data formats, not necessarily ndarray:

• array, float32array with 0..1 values
• uint8array directly

For example:
getPixels(src, { dtype: 'uint8' }, cb)

[roborourke]

Just ran into this use case when trying to use apply-cube-lut with this package. When converting RGBA channels to 0-1 values they were being rounded down.

Would be good to support the same values as the 2nd argument for ndarray-from-image.