Add input options for printing out residual vector. Useful for debugging.
Add option to output DOF constraints for debugging.
Have one of the tests print out new debugging output just to be sure.
Exit with sensible error if input file unreadable

I know this was a huge PEBKAC error, but it would have been faster to
diagnose with an earlier test and more informative error message.
Changed dirichlet bc map data structure so that BCs get applied in
the order of the input file.
Updated other dirichlet bc maps to conform to the new data structure
in the base class.
Had to update the value here. A little disconcerting because
nothing changed that should've affected it, but it was 10^-12 relative
difference, so just going with it.
Moved common functionality to base class for Boussinesq buoyancy
in preparation for stabilization term.
First draft of Boussinesq adjoint stabilization term.
Enable Boussinesq adjoint stabilization.
Convection cell now actually a convection cell

This should hit just the Boussinesq bug/instability
Merge pull request #68 from pbauman/more_debugging_output

More debugging output
Merge pull request #70 from grinsfem/test_infile

Exit with sensible error if input file unreadable
Merge pull request #69 from pbauman/dirichlet_bc_map_fix

Dirichlet bc map fix
Merge pull request #71 from pbauman/boussinesq_stab

Boussinesq stabilization