Add arguments check_cert and use_session to ArangoClient

Change default host to 127.0.0.1 from localhost

Add more user API methods and improve documentation

Update README.rst

Revamp the entire library for ArangoDB 3.x

Update README.md

Add missing simple queries in README.md

Another giant refactoring

Merge pull request arangodb#7 from Joowani/development

Development

Update README.md