Add additional arguments to numflux to allow for evolving velocities.
Clean up and optimise PlotField
Pass mx, my, mz, and vmax to the rest of the model functions.
Rename Transport to Trans always instead of just sometimes.
Make mx, my, mz, and vmax global in model.h.

Implement initial conditions for vlasov transport test case.
Add geo/square.geo for larger 2D simulations.
Intial version of vlasov transport seems ok.
Improve testmeq2 test.