Small refactors for cleanliness

src/main/java/io/zipcoder/MonkeyTypewriter.java

@@ -31,7 +31,6 @@ public class MonkeyTypewriter {
         for (Thread thread: unsafeArray) {
             thread.start();
         }
-        unsafeCopier.copied = unsafeCopier.copied.substring(1, unsafeCopier.copied.length());
 
         SafeCopier safeCopier = new SafeCopier(introduction);
         Thread[] safeArray = new Thread[5];
@@ -42,7 +41,6 @@ public class MonkeyTypewriter {
             thread.start();
         }
 
-        safeCopier.copied = safeCopier.copied.substring(1, safeCopier.copied.length());
 
         // This wait is here because main is still a thread and we want the main method to print the finished copies
         // after enough time has passed.

src/main/java/io/zipcoder/SafeCopier.java

@@ -20,7 +20,7 @@ public class SafeCopier extends Copier {
             lock.lock();
             if (stringIterator.hasNext()) {
                 String word = stringIterator.next();
-                copied = copied + " " + word;
+                copied += word + " ";
             }
             lock.unlock();
         }

src/main/java/io/zipcoder/UnsafeCopier.java

@@ -15,7 +15,7 @@ public class UnsafeCopier extends Copier {
         try {
             while (stringIterator.hasNext()) {
                 String word = stringIterator.next();
-                copied = copied + " " + word;
+                copied += word + " ";
             }
         } catch (NoSuchElementException e) { }
     }