[bugfix] Fix method subrouter handler matching (#300) (#317)

* Test method-based subrouters for multiple matching paths

* Pass TestMethodsSubrouter

* Change http.Method* constants to string literals
- Make compatible with Go v1.5

* Make TestMethodsSubrouter stateless and concurrent

* Remove t.Run and break up tests for concurrency

* Use backticks to remove quote escaping

* Remove global method handlers and HTTP method constants

route.go

@@ -75,6 +75,8 @@ func (r *Route) Match(req *http.Request, match *RouteMatch) bool {
 	if match.MatchErr == ErrMethodMismatch {
 		// We found a route which matches request method, clear MatchErr
 		match.MatchErr = nil
+		// Then override the mis-matched handler
+		match.Handler = r.handler
 	}
 
 	// Yay, we have a match. Let's collect some info about it.