Aspect::Library provides a base class for all reusable aspects, regardless of implementation.
It was created as part of the Aspect namespace reorganisation. It provides no functionality, and only
acts as a method for identifying Aspect libraries.
The original first generation of libraries are implemented via the Aspect::Modular class and are deeply
tied to it. For the second generation API this lower level base class is provided to provide a mechanism
for identifying all reusable library aspects, from either the Aspect::Modular API or independently.