Refactoring GIZMO schemes to avoid code duplication, step 1: moved MFM and MFV to subdirectories of new Gizmo directory, made common version of hydro_*.h included from rest of code that (for now) simply calls the right version.

Add kernel gamma to output

See merge request !965

Updated the main EAGLE-ICs README file to include the latest changes to SNII feedback and enrichment.

Import the sample SNII code from COLIBRE into the EAGLE feedback. Set the min SNII mass in the EAGLE ICs to 8 Msun.

When splitting self tasks, consider whether we have stars, not whether we have feedback.

See merge request !962

Fixes to the SF logger in cases of deep trees with little gas.

See merge request !963

Minor updates to the ANARCHYDU scheme

See merge request !961

Add a fake initialisation of the equation of state global objects

Closes #626

See merge request !959

Do not overflow the counter of extra particles by using a size_t where appropriate.

Closes #627

See merge request !960