#464 (#477)

* #464 added code to request mapper to not automatically add content type and content length headers, .net will automatically try and add these headers in a few circumstances but this solves the 464 issue

* #464 use seek instead of read on body check for websockets tests

* #464 ran out of inodes on linux, looks like reloadonchange causes this

test/Ocelot.ManualTest/ocelot.json

@@ -8,7 +8,7 @@
         "DownstreamHostAndPorts": [
           {
             "Host": "localhost",
-            "Port": 3000
+            "Port": 5001
           }
         ],
         "QoSOptions": {