implemented RWADef -> Swagger conversion (https://github.com/restlet/apispark/issues/1168)
added protection against NPE in the Swagger bean
added field required for Property in the RWADef bean
added field type to Parameter and PathVariable to RWADef bean
added CORS support for Swagger-UI (https://github.com/restlet/apispark/issues/1168)
updated Introspector to master's level in Swagger and APISpark extensions (https://github.com/restlet/apispark/issues/1168)
switched Introspector#getDefinition() to public, added File support, enhanced bean so that NPE protection doesn't tamper with Swagger-UI (https://github.com/restlet/apispark/issues/1168)