Changes:
* Giving/taking foxes items.
* Change taming food back to chicken.
* Change taming food to only use sweet berries.
* Child fox from breeding is now set to its parent fox type.
* Added code commenting.
* When you tame a fox it gives the player the taming advancement.
Still need to add naming.
I found out how to get my custom entity to replace the vanilla EntityFox. This should fix most of the errors people were getting.
I also rewrote the entire plugin. It saves some data with SQLite and some parts of it are cleaned up, optimized, or certain things moved in an appropriate class.