Minecraft version: 1.12.2
Forge version: 14.23.2.2654
Adventurer's Toolbox version: 0.2.7

Issue Description:

Minecraft crashes when trying to view recipe of any tool from Adventurer's Toolbox.

Steps to reproduce:

1. Click on a tool in JEI or click R while hovering over tool.

Crashlog:

https://hastebin.com/osubeseden.sql

A similar crash with the following setup:
Minecraft version: 1.12.2
Forge version: 14.23.3.2655
Adventurer's Toolbox version: 0.2.7

crash-2018-04-27_03.37.01-client.txt

This one seems to be happening specifically around flint items.