Removed ccd number from end of URI generated by resolver.
Updated ImageSliceRetriever to take into account that Fits file extensions
start at 1 not 0.
Basic DS9 image viewer class.
Putting together a hand made .astrom file that accesses some images I 
can find in vospace.  Only has one observation and one source so far.
ApplicationView is now passed a reference to the image viewer, so is able 
to start up ds9 with the image for the first observation of the first source.