Documentation on shifty

Task: shifty
Purpose: Align two images.
Categories: image analysis

        SHIFTY is a MIRIAD task which shifts one image, to that it best aligns
        with another image. Only integral pixel shifts are performed.

Key: in1
        The first input image. This is considered the master image. No default

Key: in2
        The second input image. This is the image that is shifted to make it
        align better with the master image. No default.

Key: out
        The output image. No default.