Adding a means for looking up DatastreamParsers

I am adding the parser, the means for looking up the parser, and the
lint for what a properly functioning parser shoudl look like.
Adding Entity#work_type accessor
Adding preliminary test for reifying from Fedora

An ongoing work in progress for reifying objects from Fedora into an
In Memory object.
Adding break to quickly jump out of loop
Adding Work::Property concept
Adding PropertySet concept

The Work is responsible for being the collection of properties and
other identities. The PropertySet is responsible for accepting and
routing appropriate properties.
Adding specs to PropertySet

Also tightening up behavior. Ready to connect Property and
PropertySet.
Adding 'a work entity' linters
Replacing Entity#property with hash access
Adding comparison logic
Adding properties#fetch to Entity linter
Creating initial concept of the Predicate