Merge branch 'release-0.9' into develop
Configuration initializes :default_shoulder to `EZID_DEFAULT_SHOULDER` env var (closes #27).
Merge pull request #28 from duke-libraries/27-default-shoulder

Configuration initializes :default_shoulder to `EZID_DEFAULT_SHOULDER` env var
Version 0.9.1
Merge branch 'release-0.9.1'