Report process use in MB if requested

Change marktasks to rebuild

Closes #552

See merge request !753

Only trigger an emergency sort of the stars after star formation if we are…

Closes #555

See merge request !754

No tasks for empty cells

See merge request !752

Only trigger an emergency sort of the stars after star formation if we are running with feedback (and hence need sorted stars).

Correct the condition to escape the creation of hydro tasks in the absence of feedabck in the make_hydroloop() function.

Fix typo in tracers output: Type0 and Type4 should have the same name

See merge request !751

Only set a common super-cell pointer if we are running with the policy corresponding the to the hydro/grav pointer we are looing for.

Add iact for star formation

See merge request !741

Rewrite of MPI loops - Add stellar feedback loops

Closes #522, #476, and #449

See merge request !745

Fix the random number generator

See merge request !742