Basic operator interactions for reals processing.

When the operator moves the circle around the source it now updates the location of the source in the model.  This means daophot will use the new location, and the RA/DEC for the new location will be written to the MPC file if the source is accepted.  This implements the basics (points 1 and 2) of #101.

Also found a solution for the issue of keybinds not working after left clicking image viewer.  Closes #105.