first try to merge in the scheduler_active stuff from the scheduler_skip branch. currently broken, apparently engine_collect_timestep isn't doing anything.

Now that we are skip 1, that cannot be used to pick out the active tasks for the thread info dumps, use task toc=0 instead

Strange but drift doesn't seem to visit all cells to reset this count

MPI recursion is now explicit for non-local nodes

Note there may be an issue with fixdt and sorting to resolve (these are skipped)

Revert much of last commit, need to unskip tasks of progeny as well, note this means that we cannot just skip non-local cells, we just contract to not actually drift those

All active cells must be drifted so do not skip them if rebuilding.

If rebuilding no need to unskip tasks, that will be after the rebuild

Make sure we visit all related sends of the tasks, not just of the cell

Merge branch 'mark_tasks_in_drift' of gitlab.cosma.dur.ac.uk:swift/swiftsim into mark_tasks_in_drift

This reverts commit d5191f16.

Print hostname

Prints the name of the host at runtime for each MPI rank when the verbosity level is set to 2 and the name of the host by default when MPI is not activated.

See merge request !263