Converted project to Play 2.3.2

~~Going with a release candidate due to a [bug](https://github.com/playframework/playframework/pull/3073)~~ (Play released 2.3.2 with perfect timing...)

Read the [changelog](http://www.playframework.com/changelog)

Lots of changes, mostly around...

`SimpleResult` now becomes `Result`

`Response` now becomes `WSResponse`

The `WebServices` api is split into its own project and now needs an `ExecutionContext`

The newer version of Joda Time has deprecated `DateMidnight` which we used a lot and replaced it with `LocalDate`

Changes to `Agent` e.g. there is no longer a `Agent.close()` method

Twirl is now its own project, so `Html` needs different imports

Enjoy the long pull request