Move beyond the image when zoomed in

[SpeeQz1]

When trying to move the view so that you can see beyond the borders of the image the program doesn't let you, so I am suggesting to add the ability to move the camera as that would make precise cropping much easier mostly near the borders.

[cameronwhite]

This is probably related to issue #1027 where we also need the ability to scroll beyond the edge of the image