Attempt to allow fuzzy-match filter in json-api

[cecemel]

Hello,

with regard to #60, I started implementing, or rather, looking for ways to implement extensions on the current filtering possibilities.

Some notes

General

Here, I wanted fuzzy text search on a String attribute. I validated this against the fortune-postgres, which needed to be extened too. You may find the relevant commit here: https://github.com/cecemel/fortune-postgres/commit/e80461544faf7ca7e8f46ff9a60cf6fa1f75a1e9. I didn't start a PR for this one yet. I just want first to make sure we agree on interface and how the query is passed down through all layers. So I consider this PR a base for discussion.

Regarding integration into fortune.js

I am unsure what field of request.options may be used. The fortune-postgres seemed to already use the query field, of which at first sight seemed to be the wanted escape hatch, so I didn't feel like using this.

So, as I understand it, Adapter.find leaves the possibility of extra fields on the options object unspecified. Therefore, I added fuzzyMatch on the options object.

Regarding validity JSON:API

Filtering is relatively unspecified. As such, I assume the extra filter type is legal.