Update README on how to contribute.
Merge branch 'master' into unified

* master:
  Settings changed to use default theme by default, as that's how Meph ships. :)
  The ===FOOD=== heading at OLON's no longer costs 500 silver to select.
  Update README on how to contribute.
Merge branch 'master' into unified

* master:
  maint-bin: retire nerfed_diseases branch
  Masterwork 4f release
Merge branch 'unified'. (A no-op to celebrate they're now the same!)