Memory allocations logger

Closes #414

See merge request !757

Correctly activate the feedback task over the network.

Closes #561

See merge request !776

Only check that the cells at or below the super pointer have been drifted. No drift occurs above so checking is a bad idea.

Allow the creation of hydro self-tasks in a cell that has only stars as they will be needed to set the super pointer and the corresponding drift/feedback tasks.

When forming a star in a cell that never had a star before, set the ti_old_part to the current time.

Use a better value (the default one) for the gas fraction assumed by the EAGLE SF model in the EAGLE low-z examples.

If we ran out of particles when creating a star, do not attempt to copy the properties of the gas particle to the star.

Free space used by foreign particles before attempting a repartition,

See merge request !773

Additional lock for spart creation

See merge request !774

Authorize the creation of new stars over MPI. Extra space is allocated at the end of the local cells only.