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

keep a separate log buffer per thread id. this avoids having to protect against concurrent access to the logs.

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

Fewer mpi comms

Re-think when and how we activate communication tasks and pair tasks spanning local and foreign cells.

This should result in much fewer interaction tasks, send/recv pairs, and drifts.

See merge request !373

Make SWIFT static library a dependency of all tests

We need to rebuild those after any updates.

Fixes #329. 

See merge request !376