Spice.h: 2011-02-08 Jeannie Walldren - Added documentation to methods and...

Spice.h: 2011-02-08 Jeannie Walldren - Added documentation to methods and private variables. Commented out CreateCache(double,double) since it appears that this method is not needed. Initialize pointers to NULL in Init() method.   

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@1698 41f8697f-d340-4b68-9986-7bafba869bb8