added MaterialData classes and associated Enums for COAL, CROPS, LOG, LEAVES, STEP, and DOUBLE_STEP

By: sunkid <sunkid@iminurnetz.com>

paper-api/src/main/java/org/bukkit/TreeSpecies.java

@@ -0,0 +1,58 @@
+package org.bukkit;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Represents the different species of trees regardless of size.
+ * @author sunkid
+ */
+public enum TreeSpecies {
+
+    /**
+     * Represents the common tree species.
+     */
+    GENERIC((byte) 0x0),
+    /**
+     * Represents the darker barked/leaved tree species.
+     */
+    REDWOOD((byte) 0x1),
+    /**
+     * Represents birches.
+     */
+    BIRCH((byte) 0x2);
+
+    private final byte data;
+    private final static Map<Byte, TreeSpecies> species = new HashMap<Byte, TreeSpecies>();
+
+    private TreeSpecies(final byte data) {
+        this.data = data;
+    }
+
+    /**
+     * Gets the associated data value representing this species
+     *
+     * @return A byte containing the data value of this tree species
+     */
+    public byte getData() {
+        return data;
+    }
+
+    /**
+     * Gets the TreeSpecies with the given data value
+     *
+     * @param data
+     *            Data value to fetch
+     * @return The {@link TreeSpecies} representing the given value, or null if
+     *         it doesn't exist
+     */
+    public static TreeSpecies getByData(final byte data) {
+        return species.get(data);
+    }
+
+    static {
+        for (TreeSpecies s : TreeSpecies.values()) {
+            species.put(s.getData(), s);
+        }
+    }
+}