route now takes the method in consideration

Hi,

In others frameworks (Play for example) we can use the same URI with different methods (GET and POST for example).

I made a little test program to try this in iron: http://pastebin.com/GRtmtk9T
By executing it I get the following results:

     $ curl -X POST http://localhost:3000/method
     POST
     $ curl -X GET http://localhost:3000/method
     POST

As can be seen, both POST and GET gets mapped to the same handler.

I'm creating a pull request that adds an extra method comparison to determine which handler to execute. (I'm a rust and iron newbie).