new solver -- basically the incompressible solver so far
set the BCs for the projections
note about MG changes needed
Merge branch 'python3' into LM
add a new class that inherits from the MG class
the variable coefficient variant of the MG solver will live in LM
add the abilty to define an auxillary quantity on the MG hierarchy
more progress on the variable coefficient multigrid
start of the smoothing
add the eta computations
more of the smoothing
"finish" the variable-coefficient solver -- not at all tested
take ng, also fix aux_bc
runs, but NaNs...
a test driver -- this doesn't work
gets rid of the NaNs -- we were not initializing the coefficients
at the coarsest level.  But we still don't converge.
simplify the smoothing by implementing one stencil with a loop over
the red/black sub-domains
remove redundant BC fill
had the wrong sign on f in the smoother -- still not converging
fix a sign error in the residual