added editorconfig and jshint files
- refactored grant files;
- added CHANGELOG.md;
- added notes to README.md;
- added revokeRefreshToken;
Merge branch 'master' of https://github.com/esnunes/oauthserver-mongoose

Conflicts:
	lib/grants/client-credentials.js
	lib/models/access-token.js
3.0.0