Plug and play cube caching algorithms are now possible, and filter caching...

Plug and play cube caching algorithms are now possible, and filter caching algorithm is an example of one used for programs like highpass

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@2710 41f8697f-d340-4b68-9986-7bafba869bb8