Restructured project.  There are now two main packages: gui and tools.
This is in preparation for integrating with the rest of the ossos package,
where tools will be moved up for more general use.
Removed outdated Makefile targets.
Removed docs directory (only had incomplete and out of date info).
Renamed imgviewer module to fitsviewer and MPLImageViewer class to
MPLFitsImageViewer.