Use (by default) and vectorize mip simulation

Use vectorized version for 4 or more particles.
The function now expects particle rows,
instead of a list of dictionaries with the particle momenta.
Make simulation of detector mips the default.
New subclass which just counts the number of particles.
Update test data for groundparticles

Test sim now uses compression when making the h5 file.
Add missing self.
Use correct sqrt (numpy vs math).
Suppress warnings in test from negative values in sqrt.