EulerEq: Allow use of more than one AV indicator
This adds two new options
-
av_indicator_variables
: a list of variables to which the AV indicator should be applied to. This generates one viscosity per variable. -
av_combine_operator
: an operater with which multiple viscosities are reduced to a single one.
We also re-activated the euler_sod_shock_tube_entropyav
reftest, which now seems to give acceptable results.
Also updated the euler2d_kelvin_helmholtz_entropyav
reftest, although that should not have been necessary.
However, 2d experiments are not declared stable anyways, so will need to check those later again regardless.