Fix to handle binary responses from the upstream server

src/pep.js

@@ -360,7 +360,7 @@ function respondToClient(context) {
   for (let k in context.backendresponse.headersOut) {
     context.request.headersOut[k] = context.backendresponse.headersOut[k]
   }
-  context.request.return(context.backendresponse.status, context.backendresponse.responseText)
+  context.request.return(context.backendresponse.status, context.backendresponse.responseBuffer)
   return context
 }