evolve: add ordering of the revisions for evolve --rev
When running evolve --rev we want to process the revisions in an optimal fashion
to solve the maximum amount of trouble in the minimum number of steps.
This patch adds a step to evolve --rev to order the revision before solving
the troubles. A simple test is added to cover a basic case.
doc generated with sphinx. tutorial exported using sphinxedhg
http://hg.piranha.org.ua/sphinxedhg/