Powered Thingies

- added 'fluid compound producer' (combines fluids into other fluids)
- added config files for extra recipes to various machines
    - "{registry_name}-base.json" - this is the default recipes config generated by the mod
    - "{registry_name}-extra.json" - extra recipes file that is loaded, if it exists, but will never be created/overwrited by the mod
    - check "-base.json" files for examples of the recipe structure
- improved liquid xp storage machine 
- added 'player xp addon' - you put it into a 'liquid xp storage' and you can convert stored liquid xp to/from player xp
- fixed some of the default recipes for 'powder maker'