Added the ability to import control networks, images, and shapes by right...

Added the ability to import control networks, images, and shapes by right clicking on the Project Tree. Fixes #4968.

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/branches/ipce@7858 41f8697f-d340-4b68-9986-7bafba869bb8