Simple fixes (#976)

* Should be only the really simple stuff.
* Final cleanups.

src/main/java/io/ebeaninternal/server/deploy/DeployDocPropertyOptions.java

@@ -53,7 +53,7 @@ public class DeployDocPropertyOptions {
   }
 
   private void setNullValue(String value) {
-    if (!value.equals("")) {
+    if (!value.isEmpty()) {
       mapping.setNullValue(value);
     }
   }