Add develop make target.
Use a fail-fast option for default make target.
Add close operation to Provider.
Test custom Provider method names.
Add flakes make target.
Use identity testing on boolean values.

Avoid interpreting expressions incorrectly when testing.
Add unannotate, inverse operation of annotate.
Split core API from additional in README.
Add unextend, inverse operation of extend.
Add unimplement, inverse operation of implement.