[evolve] amend: display proper error message while trying to amend non ancestor

[evolve] amend: check phase before starting the transition We better abort before starting a useless transaction.

test: turn the base public usefull for followup that test phases enforcement.

obsolete: prevent bare hg update to select hidden changeset The issue remain with branch name.

obsolete: prevent rebasing of public changeset Because we force keep we have to check this on our own.

obsolete: warn when the whole rebase set was remove because extinct

obsolete: use flag to detect that a obsolescence marker fix a latecomer Otherwise latecomer fix will be latecomer too.

stabilize: handle latecomer Merge are not handled yet.

stabilize: rework stabilize code to allow selection of latecomer and conflicting They are still unhandled but the tool now explicitly state this fact.

obsolete: add a "troubled" revset returns all changeset with troubles whatever the trouble is.

stabilize: handle killed changeset in stabilize.

stabilize: --continue support !!! Based on graft one.

stabilize: rename "node" variable to "orig" It's a not a node at all. this is a context.

obsolete Move merge failure handling into stabilize code This violate less Layer. For this purpose we crate an easy to recognize Exception Class.