Version 0.8.6

"Adding in the missing parts" edition:

New features:

• add unfold, unfold1: generate a sequence corecursively
• add memoization for iterables (imemoize, fimemoize)

Enhancements:

• call now accepts also args (see docstring)
• gtco: allow tail-chaining into any iterable
• document new features in README (also those from 0.8.5)

Bugfixes:

• fix bugs in gtco
  • strip trampolines correctly in nested generator-TCO chains
  • fix handling of generator return values