Changed how items are checked for being a valid skin target.
Fixed weapons that render more than one layer looking strange.
Allowed add-ons to add new render targets for equipment.
Added Tinkers' Construct support.
Moved Minecraft render overrides into an add-on.
Fixed most modded weapons not working with skins.
Code cleanup.
Build 0.25.0
Merge branch 'develop'

* develop:
  Build 0.25.0
  Code cleanup.
  Fixed most modded weapons not working with skins.
  Moved Minecraft render overrides into an add-on.
  Added Tinkers' Construct support.
  Allowed add-ons to add new render targets for equipment.
  Fixed weapons that render more than one layer looking strange.
  Changed how items are checked for being a valid skin target.