middleware: recovery handles panics in all handlers

Also, changes the order of the middleware so that recovery is after the
gzip middleware. Otherwise, a 200 OK is returned instead of a 500 error.

pkg/middleware/middleware_test.go

@@ -363,6 +363,7 @@ type scenarioContext struct {
 	respJson       map[string]interface{}
 	handlerFunc    handlerFunc
 	defaultHandler macaron.Handler
+	url            string
 
 	req *http.Request
 }