Fix compile warning for unit test.

Author: javadev

src/test/java/com/github/underscore/ArraysTest.java

@@ -115,6 +115,7 @@ public Boolean apply(Integer item) {
     }
 
     @Test(expected = NoSuchElementException.class)
+    @SuppressWarnings("unchecked")
     public void firstEmpty() {
         $.first(asList());
     }