2.0.0: Merge pull request #188 from tshelburne/2.0-docs

• Expanded public interface of the Loader class to support:

  • Trivial parsing of new document types
  • Custom instantiation methods
  • Custom setting of properties
  • Custom processing and fixture building

• Added support for using parameters with the following

  parameters:
      foo: value
  
  Acme\ClassName:
      property: <{foo}>