Added wordnik swagger play2 integration for API documentation

https://github.com/wordnik/swagger-core/tree/master/modules/swagger-play2
Changed filter name from toilets to restrooms to match property model name
Added construction year to Property model
Added API documentation for every controller using swagger annotations
Added routes for swagger api docs endpoints
Added security check to Facebook parseSignedRequest method.

Now it checks for encoded signature before processing.
Added support for uploading files to Amazon S3.

Also added security restrictions to file uploading.
Added Json serialization for datetime fields to ISO-8601

(yyyy-MM-dd'T'HH:mm:ss)
Also added it to every model with a datetime field
Added updatedDate to Property model.

Also overwritten update method to update updatedDate to current date
Added lastUpdated filter to Property list action, it filters properties updated after given date
Added Postmark Mailer service, also added a PostmarkEmail model to create and send emails easily