Breaking Changes:

* Rename SimpleFixedInvExtractable to SimpleFixedItemInvExtractable
* Rename SimpleFixedInvInsertable to SimpleFixedItemInvInsertable
* Moved IListenerToken out into it's own file
* Made CacheInfo's no-arg constuctor private (as there's no cache information available yet)

Changes:

* Added fluid attributes as a nearly identical copy of the item attributes
    * Instead of ItemStack everything is based on "FluidVolume" and "FluidKey"
        * FluidKey is an immutable class with 2 fields: minecraft's Fluid class, and a CompoundTag.
        * FluidVolume has Fluid, CompoundTag (modifiable), and amount (also modifiable).
    * Everything filter wise is based around FluidKey, while everything else is based around FluidVolume
