Minor edits to stabs/graded action and RABL
stabs/dated also used in student console
Added method to stats on stab quality for a given question ...

The stats are used render bar-graphs (viewable by students)
Group scans for stabs by stab-id
Allow processing of any json key within preview.loadJson

We still don't have a use-case for when preview.images is an
array of hashes. But it was anticipated and some code changes made.
Those changes have now been made generic
Added method to return text-version of stab quality
Different json for stabs/dated depending on who is calling (student/examiner)
Wide-Y styled the same way as wide-X
Carousel controls should have a z-index > overlay
Loading bell-curve for each stab
Merge branch 'puzzle'