[Coin-lpsolver] Sbb infeasibility status

[Lou Hafer]

Jean-Sebastian,

	As far as I know, there's no real significance to either number
(1.0e30, 1.0e50) other than they are larger than any objective one should see
in a real problem. At a quick guess (I haven't poked at the code in a few
months), sbb doesn't report proven infeasible because it never checks. It'll 
just stop without reporting a solution, or you'll get a message about `No 
integer solution found.'

	Likely the place to put a check is in branchAndBound(), down toward the
end. Like this:

if (bestSolution_)
{ ... stuff to restore the optimal solution ... }
else
if (isProvenInfeasible())
{ ... print a message ... }

I'll see if I can work this in, if John doesn't beat me to it.

						Lou