[wip] adding jsonld context, .jsonld format

As per [#42](https://github.com/jsonresume/resume-schema/issues/42) and [schema PR](https://github.com/jsonresume/resume-schema/pull/83).

Adds Travis-CI config, and tests for user create, user add, resume add, get context and get resume (json and jsonld).

Here's a build:
https://travis-ci.org/bollwyvl/registry-server/builds/29566766

Hope this turns out to be interesting!