New OPM Health Status Report

I'm not finished with this, but the structure is all there, and it's just a matter of continuing to add indicators.  I figure we should get this reviewed and merged, then subsequent changes can be quick and easy to get in.  This doesn't affect any existing reports, it's an additional report which the partner knows is in the alpha stages.
@czue
I overrode the parent class's `headers` method to provide help text.  Now the columns have very terse headers, with a more verbose explanation on hover.  We might need to work out a key of some sort for printed reports, but I figure this'll help eliminate some confusion over what the indicators mean.