build.properties: Upgraded SBT from 0.13.0 to 0.13.5-M2.
plugins.sbt: Upgraded Play! from 2.2.1 to 2.3-M1.
build.sbt: Replaced Build.scala, migrated to Play! 2.3, and increased version to 0.5.3-RC1.
providers/oauth2: Migrated WS to Play! 2.3's package structure and replaced WS.Response with WSResponse.
TwitterAuthProvider, XingAuthProvider: Migrated OAuth to Play 2.3's package structure and use public fields instead of methods when accessing OAuth.RequestToken.
OpenIdAuth*: Migrated OpenID to Play 2.3's package structure and fixed Promise.get() call.

OpenIdAuthProvider#authenticate(): Added missing timeout when calling
Promise<String>#get(). This might change the behaviour of this method in
an unexpected way.
LinkedInAuthProvider: Migrated OAuth to Play 2.3's package structure and use public fields instead of methods when accessing OAuth.RequestToken.
OAuth1AuthProvider: Fix pkg structure, OAuth.retrieveAccessToken() call, and WS call.

Migrated OAuth to Play! 2.3's package structure.

OAuth.retrieveAccessToken() no longer returns Scala.Either. It throws a
RuntimeException instead. Changed #authenticate() to reflect this fact.
This change might affect the behaviour of this method.

WS.get() in Play! 2.3 returns Promise instead of Future and WSResponse
doesn't have the method json(). Changed #signedOauthGet() to reflect
these facts. This change might affect the behaviour of this method.
Merge pull request #173 from generify/2.3.x

2.3.x