Abstract object construction to providers (again). Dependencies interface products with scope.
Added blank RVTScope class and spec.
Changed constructor injection tests to a spec.
Implemented singleton scope.
Group classes into folders.
Added enter/exit methods for scopes.
Scopes act as intermediary between dependency and providers. Added 'no scope', and scope cache for singleton scope.
Dependency map creates its own mutable dictionary (the map is itself a data structure, so there's no need to pass in a different kind.)
Fix initializer recursion.
Remove logging.
Added pizza module, and incomplete providers spec.
Added resolved dependency provider.
Added resolver and extractor, for dealing with nested providers.
Added podspec for 0.0.1.
Added version file.