Add jsonlint-py maker
Add jsonlint-py maker

ref http://deron.meranda.us/python/demjson/

Closes https://github.com/neomake/neomake/pull/873.

neomake/neomake,codeinabox/neomake,bonds/neomake,nerdrew/neomake,nerdrew/neomake,datanoise/neomake,euclio/neomake,euclio/neomake,bonds/neomake,neomake/neomake