Align the runner structures on a memory bound.

Closes #395

See merge request !481

We might hope to be clean against all the issues it identifies

Fix the logging of neighbour ids in doself_subset_vec. Pull ids from main cell…

See merge request !479

Fix the logging of neighbour ids in doself_subset_vec. Pull ids from main cell instead of subset parts array.

Make use of a temporary threadpool in the reading routines to speed-up the duplication of parts into gparts.

Added support for more Kaby-Lake CPUs. Also added better defaulting options for older GCCs to cope with this unknow architecture.

Correctly compute the separate time-bins for hydro and gravity at the bottom of the tree in space_split_recursive()

In the gravity FFT task only verufy if the multipoles are drifted when the debugging checks are activated.

Print more information about multipoles and cells when an undrifted multipole is encountered in the MM task.

Set the nodeID for the engine and the cells to be the same.

See merge request !476

Dopair vec mpi

See merge request !456

Make the hydro schemes compute the dirfted velocities themselves when collecting statistics.

See merge request !474

Removed the now obsolete checks that all correct tasks are active. Will need to be re-done correctly.

Add a SWIFT_DEVELOP_MODE flag to enable development code options

Closes #391

See merge request !473