Allow handlers to return a status code
Don't use the first value as a status code if not an integer
fixed serving default `index.html`

See [net/http](http://golang.org/src/pkg/net/http/fs.go#L314)
feat: Add http verb PATCH to router
Remove filepath join
docs: Add `PATCH` documentation to README
Merge branch '67-patch-method' of github.com:cgarvis/martini into cgarvis-67-patch-method