Jsonplay

Closes #8

See merge request !9

Bug-fixes and improvements:
* Closes #5
* Closes #1
* Adds Client (beta)
* Added several schemas
* Lighter string representation -> should avoid delays in the analysis
  with plugins that have 'heavy' attributes

Backwards-incompatible changes:
* Context in headers by default
* All schemas include a "@type" argument that is used for autodetection
  in the client

... And possibly many more, this is still <1.0

* Replaced gevent (testing)
* Trying the slim python image (1/3 of previous size)

This should help with performance issues with models that have large
private variables.

This allows for better framing when two entries have the same @id

* Added pre-commit: http://pre-commit.com
* Fixed flake8 errors
* Added flake8 pre-commit hooks
* Added pre-commit to Makefile
* Changed VERSION numbering
* Changed versioning to match PEP-0440

* Added debug Dockerfile/Makefile
* Validation of examples in docs

* Downloads pip requirements
* Modified Makefile

* Updated sphinx docs to include schemas and version
* Added docker push to makefile

Also:
 * Shelve -> Pickle to avoid weird db problems
 * Serving schemas and contexts

Also:

* added drone-ci integration: tests for py2.7 and py3

There are also some slight changes to the JSON schemas and the use of
JSON-LD.