Migration to Play 2.3

Change Scala and Play versions
Use play.api.mvc.Result instead of SimpleResult
Add special class with no args constructor to support Java
Rewrite it like this
```scala
class JsonpJava extends Jsonp(Jsonp.DefaultParamName)(utf_8, defaultContext) {
```

Not sure about factory because Java Global object has this signature for filters:
```java
public <T extends EssentialFilter> Class<T>[] filters();
```
So I should construct array of classes (not instances) with no args constructor in every class.
Maybe there is a way to write no args constructor in Jsonp.scala. I don't know Scala :)