Refactoring to make session more prominent.  Allow names of environment variables to be overridden when creating a session.  Add initial docs.
Added support for reading AWS_CREDENTIAL_FILE
An updated ec2.json file and first attempt (untested) at adding govcloud region.
Merge branch 'develop' of git://github.com/paulegan/botocore into paulegan-develop
Adding a doc string and changing search order so that a new style config file, if found, will take priority over an old one.