Add the possibility to read basic chemistry information from the parameter file and propagate this onto the particle at initialisation time. More uniform naming convention for the first initialisation of properties.

Better naming convention for the cell_split variables in the YAML file. New variable for the splitting of gravity pairs.

This reverts commit 10f04895.

Re-introduce the 'end_force' function as a task in order for the cooling function to be called at the right place in the time-step.

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

Separate the time-step information for hydro and gravity tasks into two different set of variables for each cell.

Fixed a moronic bug. Unskipping MPI sends and recvs for gravity should not be done *only* for local pairs. Obviously....

Instead of listing local cells only, list cells that have a tasks associated with them on the local node.

All-reduce all the top-level multipoles after a rebuild() to make sure we have all information in hands to construct the tasks.

Force compiler to report shadowed variables. Removed all shadowed variables. Added the function scheduler_activate_send() to simplify the unskipping of MPI sends.

Lots of refactoring to tidyup code reuse