Adds the SodShock BCC test and updates SquareTest

This MR does two things:

• Updates the SquareTest to use a smoothed profile for quantities in the plotting script, as well as includes a script for making ICs with different mass-particles
• Adds the SodShock_BCC_3D test which uses a BCC configuration for the ICs rather than the regular glass file.
• Also updates the HydrostaticHalo test to work with python3.