cleaning up the controller

performing config checks.
changing some constant names.
reordering the flow
making the Gatherer interface runnable

generalizing the gatherer in controller.
implementing local file gatherer
documenting the controller

adding javadocs.
removing some unnecessary methods.
enhancing some methods.
cleaning up the FITS adaptor

cleaning up the FITS adaptor.
getting rid of unnecessary references.
documenting the class.
fixing failing test

a test was failing due to config change.