Add required option to field definitions
Make sure optional plays well with auto_now
Merge pull request #63 from spiral-project/optionalfield

Add required option to field definitions (ref #55)
Change the API endpoints and clean the code.

* Change the REST API resources.
  Use /models/:model-id/{definition,data} rather than {/definitions,/data}/:model-id
* Fix some database issues in the CouchDB backend
* Removed the tokens
* Removed the lettuce tests
merge dev with master
Implement PATCH on data items (ref #41)

Cherry-picked from an old commit by @AntoineCezar and updated to the new structure of daybed by @ametaireau and @natim
Add a POST method for definitions (ref #14)
Refactored the model REST API for POST and PUT.

A Model contains both a definition and a list of data items.
When POSTing to /models you need to provide a definition and some data items, which changes the API contract we have when we PUT on /models/:model-id/definition.

You also can pass some data there, which will be created if they validate the definition.

r=@Natim
Add authorization policies
GeoJSON renderer (ref #12)
Return with JSON Content-type (ref #12)
Return original JSON serialization if any bit missing (ref #12)
Basic GeoJSON serialization test (ref #12)
Basic GeoJSON now passing (ref #12)
Merge branch 'master' into dev
Pep8ify
Add hello view with version (fixes #69)
Pass DB instance from validators to field types (ref #32)
Test relation types (ref #32)
Merge branch 'dev' into geojson