changed so that variable input from config file and some internal storage uses...

changed so that variable input from config file and some internal storage uses display name (or a more abstract variable key) in order to allow multiple virtual data sets from the same variable to be present in a single configuration file

git-svn-id: https://svn.ssec.wisc.edu/repos/glance/trunk@55 8a9318a1-56ba-4d59-b755-99d26321be01