[#905] Validate datastore actions against a schema
[#905] Do not raise 500 if the wrong type is passed to datastore_create or datastore_upsert
[#905] CLean up import, capitalized constants
[#905] Add missing schema file. Thanks @tobes
[#905] Explicitly get validators from toolkit
[#905] Get OneOf from toolkit
[#905] Validate filters and parse them to json, even if they are strings, fixes #917
[#905] Fix pep8 isssue
[#905] Sort imports correctly, improve PEP8, remove unused code
Merge branch 'master' into 905-datastore-validation

Conflicts:
	ckanext/datastore/db.py
	ckanext/datastore/plugin.py
[#905] Fix merge, add limit and offset parameter to dump which is compatible with new schema validation
[#905] Do not require PEP8 blacklisting any more
Merge branch 'master' into 955-datastore-alias-clashes

Conflicts:
	ckanext/datastore/db.py