Feature/fix tracing (#297)

* hacked together tracing fix by wrapping middleware delegate in another delegate

* #227 have re-implemented tracing, cleaned up trace names, probably still need some refactoring and tests as this was a bit of a hack job

* #227 bit of checking for when we dont want to use tracing, also removed a unit test for websockets that wasnt a unit test, i stuck it there because i wanted the code coverage and now im paying the price, will have to work out a better way to do it

* #227 a bit of refactoring to make this work better, still a bit hacky...would like to revisit the whole thing one day

* #227 dont need this

* #227 or this

* #227 small refactor

test/Ocelot.ManualTest/appsettings.json

@@ -2,7 +2,7 @@
   "Logging": {
     "IncludeScopes": false,
     "LogLevel": {
-      "Default": "Debug",
+      "Default": "Error",
       "System": "Error",
       "Microsoft": "Error"
     }

test/Ocelot.ManualTest/configuration.json

@@ -99,7 +99,7 @@
       "HttpHandlerOptions": {
         "AllowAutoRedirect": true,
         "UseCookieContainer": true,
-        "UseTracing": false
+        "UseTracing": true
       },
       "QoSOptions": {
         "ExceptionsAllowedBeforeBreaking": 3,