WIP. Instance role support.
Add support for temporary security credentials. #4
Merge branch 'instance-role-auth' into instance-auth

* instance-role-auth:
  WIP. Instance role support.
Add InstanceKeys and EnvKeys functions. #4
Support for intance-based IAM role credentials in gof3r. #4
Merge pull request #6 from rlmcpherson/instance-auth

Instance auth