ds9 7.3.2 (new formula)

SAOImage DS9 is an application for astronomical image analysis (see http://ds9.si.edu/).

 + The app is the newest version and is complied from source.
 + All dependencies are included in the tar.gz file downloaded from their website.
 + I have disabled code signing as we don't have an identity, and because we are not building an .app, we don't have to worry about MacOS developer identification.
 + DS9 has no CLI, so the test I have included opens up DS9 in X11, prints a message, and then closes again.