Adjust checkstyle rules. Make checkstyle fail the build when violations are found. Correct all current checkstyle violations.

twin/src/main/java/com/iluwatar/twin/BallThread.java

@@ -19,6 +19,9 @@ public class BallThread extends Thread {
     this.twin = twin;
   }
 
+  /**
+   * Run the thread
+   */
   public void run() {
 
     while (isRunning) {

twin/src/main/java/com/iluwatar/twin/GameItem.java

@@ -9,9 +9,6 @@ public abstract class GameItem {
 
   /**
    * Template method, do some common logic before draw
-   * 
-   * @param other
-   * @return
    */
   public void draw() {
     System.out.println("draw");