Fixes #287 by no longer opening cubes for every measure when only Residual or...

Fixes #287 by no longer opening cubes for every measure when only Residual or Shift tolerances are being validated, neither of which require anything more than information stored in the Control Measure itself

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@2932 41f8697f-d340-4b68-9986-7bafba869bb8