Makes it possible to support other "function" types in the future.
The user is always taking a risk with the lookup that the object
returned has the generic type desired (but that hasn't changed
with this commit). FunctionCatalog is a lot simpler as a result
and also a lot more flexible.
- attempted to make code more functional (eat our own dog food) and concise
- addressed PR comment
- additional cleanup/polishing of FunctionUtils and related classes
- Removed Function/Supplier/ConsumerProxy classes by extending type info on their super interface
- Renamed FunctionUtils to FunctionFactoryUtils
- Added javadoc to FunctionFactoryUtils to explain its design considerations as well as what it can and can not doi
Fixes gh-90