Access to more libMesh DiffSystem params

This depends on https://github.com/libMesh/libmesh/pull/359
Add option to plot VelocityPenalty parameters
VelocityPenalty postproc bugfixes

Make sure we get the right gradient components in the right places
Mark old config name as deprecated
Merge pull request #147 from grinsfem/velocity_penalty_postproc

Velocity penalty postproc
Merge pull request #146 from grinsfem/print_diffsystem

Access to more libMesh DiffSystem params
Use a more stable sign on VelocityPenalty force

We were antidissipative before; we should be dissipative now.

This commit also has the beginnings of the code for a term with no
energy addition *or* subtraction, but that may not be working right
yet.
Adjust penalty_poiseuille regression test

This should pass with the new VelocityPenalty sign.  Solution still
looks good to the eyeball but has some small numerical diff.
Tweaks for laspack, skip one regression

Configuring against laspack was an accident, but we might as well get
tests working with it where we can.

I'm returning 77 to skip the low_mach_cavity regression.  My
hypotheses about it have all failed, I don't have time to bisect it
now, and I'd like to be able to get a quick yay/nay report on possible
future regressions with this "false positive".
Merge pull request #149 from grinsfem/velocity_penalty_fixes

Velocity penalty fixes
Clearer error message in IC handling
Merge pull request #150 from grinsfem/more_tolerances

Tweaks for laspack, skip one regression
Merge pull request #151 from grinsfem/IC_handling_errmsg

Clearer error message in IC handling
Update for compatibility with current libMesh
Refactor VelocityPenalty, add stabilization

So it turns out that you *can't* always get away with an
residual-inconsistent stabilization method.  Let's start to work on
fixing that.
Add VelocityPenaltyAdjointStabilization test
Fixes for Jacobian errors

We still seem to be about 0.1% off...
Numerical Jacobians for penalty_poiseuille_stab

We'll use this until the analytic Jacobians' error is found.
Add penalty_poiseuille_stab regression values
Merge pull request #152 from grinsfem/velocity_penalty_stab

Velocity penalty stabilization