Internet Explorer Upgrade header compatibility

Author: Mikanoshi

AndroidAsync/src/com/koushikdutta/async/http/server/AsyncHttpServer.java

@@ -248,7 +248,7 @@ public void onRequest(final AsyncHttpServerRequest request, final AsyncHttpServe
                         }
                     }
                 }
-                if (!"websocket".equals(request.getHeaders().getHeaders().get("Upgrade")) || !hasUpgrade) {
+                if (!"websocket".equalsIgnoreCase(request.getHeaders().getHeaders().get("Upgrade")) || !hasUpgrade) {
                     response.responseCode(404);
                     response.end();
                     return;