Fix compiler warnings.

Author: javadev

src/test/java/com/github/underscore/lodash/MathTest.java

@@ -254,6 +254,7 @@ public double doubleValue() {
 _.subtract();
 => null
 */
+    @SuppressWarnings("unchecked")
     @Test
     public void subtract() {
         assertEquals("-1", U.subtract((byte) 1, (byte) 2).toString());

src/test/java/com/github/underscore/lodash/StringTest.java

@@ -3603,7 +3603,7 @@ public void main() throws Exception {
         U.main(new String[] {});
         new U<String>(new ArrayList<String>());
         new U<String>("");
-        new U<Object>(Arrays.asList()).chain();
+        new U<Object>(Arrays.<Object>asList()).chain();
         new Json.JsonArray();
         new Json.JsonValue();
         new Json.JsonObject();