Merged gravity M-M tasks
Merge the M-M tasks between two cells into one single M-M task that will perform all the operations on the pair's progenitors.
Additional changes are:
- Delay the drifting of the multipole to the task instead of the unskip.
- Use the CoM at rebuild time in
cell_can_use_pair_mm_rebuild()
as the name indicates. - Add extra timers to
engine_maketasks()
- Use the list of local cells (instead of all cells) in
space_regrid()
to infer the maximal smoothing length. - Fix the plotting scripts for matplotlib 2.x.
- Change the task flag to a
long long
instead ofint
.