v2.0.5

• Adds support for resolving Protocol classes even when they don't define an
  __init__ method, by @lucas-labs
• Fixes bug in service provider build logic causing singletons to be instantiated
  n times when they are registered after its dependant, by @lucas-labs
• Changes the "ignore attributes" logic so that if a class variable has already
  been initialized externally, rodi doesn't attempt to reinitialize it (and to
  also prevent overriding it if the initialized class variable is also a
  registered object), by @lucas-labs