Refactor options rebase

The idea is to get 1.0.0 of this module shipped, with a lot of breaking changes which are needed, there are a couple of others left (e.g. integrate the new hock api plus returning `err, server` instead of just server:

Two major changes included: 

1. sane option parsing (thx @domenic for the input)
2. Fix clashing filteringPath and plugins after 

Breaking changes:

 - options must be of type `object`
 - `minReq` & `maxReq` are now `min`and `max`
 - a "plugin" is injected via options.plugin, not as a mock
   being a function
 - a plugin does not override the default routes any more
 - `{"error":"version not found"}` is returned after the limit of
   requests is reached instead of `No Matching Response!`