Changed the namespacing/directory structure so we actually use this :gem:'s namespace for what it adds
Refactor to defer to a Holding object that can be used downstream
Holding doesn't need to go to a Hash
Add examples for expanded, from aleph and requestability
Add <status>? methods to holdings
Change AvailabilityStatus to DisplayStatus; fixes #21
Merge pull request #25 from NYULibraries/feature/refactor_helper_classes

Refactored helper classes.
Closes #23, #22, #20, #18.