applied naming policy (https://github.com/restlet/apispark/issues/1439)

renamed SwaggerConverter and RamlConverter to [Language]Translater, and [Language]ConversionException to a unique class TranslationException
added RWADef version to the class Definition (https://github.com/restlet/apispark/issues/1439)
fixed schemas part (https://github.com/restlet/apispark/issues/1439)

changed out/in representation declarations to match RAML specs, same for $ref property, implemented required and uniqueitems support for Representations Properties
flattened resources (https://github.com/restlet/apispark/issues/1439)

nesting resources in RAML is complicated to automate and does not bring much, will be re-evaluated if the definitions are too heavy
fixed bugs due to non re-initialization of objects (https://github.com/restlet/apispark/issues/1439)
removed useless v in front of version number (https://github.com/restlet/apispark/issues/1439)