test-evolve-bumped: improve tests legibility This patch introduces in test-evolve-bumped some of the test helpers that we use in other tests to make the code more legible.

evolve: drop len comparison in prune and fold Computing the length of a smartest may be significantly more expensive than computing it length.

evolve: add an help topic about evolution The text is probably bad, but this have been laying around for quite sometime (with Mercurial core in mind) lets move forward and add this to evolve.