The example app is a command
Fix router tests

These were introduced by breaking changes in the following commits:
- aca58b22cfe17db7c5fc9a94c1ab647c6783cd08 (ValidMethodsKey)
- 386323a6edcd74962da674f36df8489f5b1fbe4b (HTTP methods are case sensitive)
Replace Sub() with trailing * in patterns

This change replaces a bit of API surface area (the Sub() method on Muxes) with
a slightly more expressive pattern syntax. I'm mostly doing this because it
seems cleaner: the "*" gets to take on a meaning very similar to what it means
in Sinatra (without growing regexp-like middle-of-a-path globbing, which sounds
terrifying and not particularly useful), and we get to nuke a useless function
from the API.