#638: Add CreativeCategory API for Materials

By: Parker Hawke <hawkeboyz2@hotmail.com>

paper-api/src/main/java/org/bukkit/inventory/CreativeCategory.java

@@ -0,0 +1,53 @@
+package org.bukkit.inventory;
+
+/**
+ * Represents a category in the creative inventory.
+ */
+public enum CreativeCategory {
+
+    /**
+     * An assortment of building blocks including dirt, bricks, planks, ores
+     * slabs, etc.
+     */
+    BUILDING_BLOCKS,
+    /**
+     * Blocks and items typically used for decorative purposes including
+     * candles, saplings, flora, fauna, fences, walls, carpets, etc.
+     */
+    DECORATIONS,
+    /**
+     * Blocks used and associated with redstone contraptions including buttons,
+     * levers, pressure plates, redstone components, pistons, etc.
+     */
+    REDSTONE,
+    /**
+     * Items pertaining to transportation including minecarts, rails, boats,
+     * elytra, etc.
+     */
+    TRANSPORTATION,
+    /**
+     * Miscellaneous items and blocks that do not fit into other categories
+     * including gems, dyes, spawn eggs, discs, banner patterns, etc.
+     */
+    MISC,
+    /**
+     * Food items consumable by the player including meats, berries, edible
+     * drops from creatures, etc.
+     */
+    FOOD,
+    /**
+     * Equipment items meant for general utility including pickaxes, axes, hoes,
+     * flint and steel, and useful enchantment books for said tools.
+     */
+    TOOLS,
+    /**
+     * Equipment items meant for combat including armor, swords, bows, tipped
+     * arrows, and useful enchantment books for said equipment.
+     */
+    COMBAT,
+    /**
+     * All items related to brewing and potions including all types of potions,
+     * their variants, and ingredients to brew them.
+     */
+    BREWING;
+}