let the api_version be set in the settings
When you get HTTPErrors from twilio, log them better.
(cherry picked from commit e9889fbcb9a70b0fc3100548dcabe81a39b5515a)
Merge pull request #2 from czue/error_response

When you get HTTPErrors from twilio, log them better.
Merge pull request #1 from czue/4ca5b4aef7f711630a9ed1071fd4f7c257a8cbf4

Minor change, if we want to support different api versions
Merge branch 'master' into develop
Merge branch 'develop' into feature/new-routing

Conflicts:
	README.rst
	rtwilio/backend.py