cmake config can no toggle the use of "NDEBUG" or "USE_TIMINGOUTPUT"
compiler flags, hence source files and/or .bashrc no longer need to be changed
themselves.
I'm not sure the mechanism survives very nicely for executable
compilation, but it's better to have it and figure that out later.

change actually made by chichi on Tobias's computer.
blame him.

launcher checks that stored iteration and checkpoint in <simname>.h5 are
consistent, i.e. <simname>_checkpoint_<checkpoint_value>.h5 contains
field at iteration.
useful when DNS are restarted for various reasons.

also corrects `joint_acc_vel_stats`, in the sense that forcing
parameters should be read beforehand if the acceleration statistics are
to make sense.

not really used now, but I might as well

if stop_<simname> exists, script removes it.