2.0 migration guide

LibGui 2.0 has some breaking changes. Here are the main things you need to update:

• CottonCraftingController has been replaced with SyncedGuiDescription, which doesn't take a recipe type.
• Custom widgets
  • WWidget.paintBackground has been renamed to paint. It now also takes the MatrixStack used for screen rendering.
  • All text rendering methods in ScreenDrawing also take a matrix stack now.
• Background painters
  • VANILLA_9PATCH was renamed to VANILLA and the old VANILLA was removed.
• WItemSlot's unused ltr constructor parameter was removed.