In CubeIoHandler, modified the findCubeChunks, writeIntoDouble, and...

In CubeIoHandler, modified the findCubeChunks, writeIntoDouble, and writeIntoRaw methods to handle repeating virtual bands. In cubeatt, added an app test for repeating virtual band input. Fixes #1927.

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@5764 41f8697f-d340-4b68-9986-7bafba869bb8