Make sure the GIZMO extra loop uses the in and out ghost tasks and not just the main ghost task. Code formatting.

Revert "Add checks for particles that are at same position, this isn't allowed, and update the cell h_max to that of the particles after the initial ghost tasks have ran. This is needed before regridding if the h values of the particles in the IC are set to be smaller than reality (ends up looking like rebuilding failed as the particles are too far outside their cells)."

This reverts commit 3d12f382.

Add checks for particles that are at same position, this isn't allowed, and update the cell h_max to that of the particles after the initial ghost tasks have ran. This is needed before regridding if the h values of the particles in the IC are set to be smaller than reality (ends up looking like rebuilding failed as the particles are too far outside their cells).

Use the basename for the HDF5 files

These are relative to the container file and could include directory information (we assume XMF file is written into same directory as the snapshots).

Fixes #325.

See merge request !369

Use the basename for the HDF5 files as these are relative to the container file and could include directory information (we assume XMF file is written into same directory as the snapshots).

Subsize

Use separate parameters to determine when a pair or self interaction should be made a sub-cell task.

See merge request !365

Check if snapshot directory exists and add a digit to the output

Fix issue #321 

See merge request !368

This is a requirement of fopen()

Conflicts:
	src/space.h

Updated the default values of space_subsize_pair space_subsize_self to the optimal values found in a parameter search using EAGLE_25 on 16 cosma-5 cores.

Removed the now unused space_maxcount global variable. Documented the new YAML parameters in the example parameter file.

Remove 8-cell limit in gravity + non periodic case

Fix issue #323 

See merge request !367

Also use errno to get the detailed error about the failure

Subset sorting

Massive change in the way we treat sub-cell tasks and sorts in general, i.e.:

 * Sorts and drifts now unlock *all* sorts and drifts above them, this ensures they are executed bottom-up even if intermediate tasks are not active,
 * Sub-cell task hierarchies are traversed consistently during density/ghost/force computations,
 * Sub-cell tasks no longer do the drifting and sorting themselves,
 * Sorts are only re-computed once the oldest sorted index goes stale.
 * Ghosts exist at a lower level in the tree.

See merge request !343

This would have revealed the last MPI bug a but quicker