Fixes issue #191. Allows escaping of URL parameters so that ":" can be u...

...sed literally in URL.

### Resubmitting for Travis build

**Example**
Specifying the route:
`/api/posts/::post/comments/::id`
Will match the URL:
`/api/posts/:post/comments/:id`

This is particularly useful in creating OPTIONS routes that contain documentation about an API.