Remove max change in `u`
The code still defines const_max_u_change in const.h but never makes use of this constant despite printing it to the screen when describing the hydro schemes. If this is true, we should get fully rid of it.
The code still defines const_max_u_change in const.h but never makes use of this constant despite printing it to the screen when describing the hydro schemes. If this is true, we should get fully rid of it.