Improved model referencing

In my application I have several modules and each module may specify its own Swagger API, which will then be cumulated to a single Swagger API. The modules may now specify various models and to keep the API clean I would like to use some kind of module prefix in the model IDs. The model IDs support that, but the reference item currently matches against `\w+`. I extend the `\w` character class by a few commonly used separators, namely `. _ / \`.