Added heldList functionality back to jigsaw. Can hold non-overlapping images...

Added heldList functionality back to jigsaw. Can hold non-overlapping images during a bundle adjustment. Turned off solving by sensor (turned off USEPVL, SC_PARAMETERS). Fixes #4293.

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/branches/ipce@7162 41f8697f-d340-4b68-9986-7bafba869bb8