Permit periodic task instead of PlayerMoveEvent through NPCLibOptions

Adds NPCLibOptions as an optional parameter to NPCLib's constructor. The
movement handling specified by the NPCLibOptions will determine whether
to use the PlayerMoveEvent or a task.

api/src/main/java/net/jitse/npclib/NPCLibOptions.java

@@ -0,0 +1,77 @@
+package net.jitse.npclib;
+
+/**
+ * Mutable preferences for library usage
+ * 
+ * @author A248
+ *
+ */
+public class NPCLibOptions {
+
+	MovementHandling moveHandling;
+
+	/**
+	 * Creates the default options
+	 * 
+	 */
+	public NPCLibOptions() {
+		moveHandling = MovementHandling.playerMoveEvent();
+	}
+
+	/**
+	 * Specifies the motion handling which will be used for the library. <br>
+	 * Programmers may choose between using the PlayerMoveEvent or
+	 * a periodic task. <br>
+	 * <br>
+	 * Note that NPCLib will always use events such as the PlayerTeleportEvent
+	 * and PlayerChangedWorldEvent in addition to the specified option.
+	 * 
+	 * @param moveHandling the movement handling
+	 * @return the same NPCLibOptions
+	 */
+	public NPCLibOptions setMovementHandling(MovementHandling moveHandling) {
+		this.moveHandling = moveHandling;
+		return this;
+	}
+
+	/**
+	 * Options relating to movement handling
+	 * 
+	 * @author A248
+	 *
+	 */
+	public static class MovementHandling {
+
+		final boolean usePme;
+		final long updateInterval;
+
+		private MovementHandling(boolean usePme, long updateInterval) {
+			this.usePme = usePme;
+			this.updateInterval = updateInterval;
+		}
+
+		/**
+		 * Gets movement handling using the PlayerMoveEvent
+		 * 
+		 * @return movement handling
+		 */
+		public static MovementHandling playerMoveEvent() {
+			return new MovementHandling(false, 0);
+		}
+
+		/**
+		 * Gets movement handling using a periodic update interval in ticks.
+		 * 
+		 * @param updateInterval the update interval in ticks
+		 * @return movement handling
+		 */
+		public static MovementHandling repeatingTask(long updateInterval) {
+			if (updateInterval <= 0) {
+				throw new IllegalArgumentException("Negative update interval");
+			}
+			return new MovementHandling(true, updateInterval);
+		}
+
+	}
+
+}