Introduce maximum strength cap (implemented, not fully tested).
Implemented zero-cost factories. Not fully tested.
Introduce interfaces for factories - these will be renamed soon.
Split out access to internal node property on a factory into an internal interface, as it should be.
Rename factory interfaces to follow the 'INameOfInterface' convention.
Merge in strength caps, zero-cost subtrees, plus breakout of factory API into interfaces.
Update NTestCaseBuilder NuGet package to 2.1.0.0.
Merge latest changes from 'main' - brings in new interfaces for factories, plus strength caps and zero cost subtrees.
Remove unused directory.
Merge in new interface APIs for factory plus strength caps and zero cost subtrees. This may need some fixing up in the next commit.
Produce NTestCaseBuilder.Samples 2.1.0.0.