fixed CORS PreFlight
<init-param>
<description>A comma separated list of allowed headers when making a non simple CORS request.</description>
<param-name>cors.allowed.headers</param-name>
- <param-value>X-FHIR-Starter,Origin,Accept,X-Requested-With,Content-Type,Access-Control-Request-Method,Access-Control-Request-Headers</param-value>
+ <param-value>X-FHIR-Starter,Origin,Accept,X-Requested-With,Content-Type,Access-Control-Request-Method,Access-Control-Request-Headers,Prefer</param-value>
</init-param>
<init-param>
<description>A comma separated list non-standard response headers that will be exposed to XHR2 object.</description>
