[state] Update doc on the mutable property of state (and the way it's implemented)

[state] add mutable property to state object.

[states] add a todo related to MQ

[states] fix a bug with rebase --detach There is unexpected (for me) content in state.

[states] add mq support

[states] add rebase support.

[states] move IO logic outside the repository subclass This is meant to lighted this part a bit

[states] add a small paragraph about controlling permision to move the boundary

small refactoring and big doc update. Sorry for the big commit crecord one so much diff seems to confuse my powerbook to death :-/

move part of the readme about states in states itself.

[obsolete] Fix pushkey

Use dedicated mechanism to report pushkey success

[obsolete] Update pushkey code

Update pushkey code to be able to push ready heads too.

Make states more resilient to missing head In particuliar pushkey is now more robust (with a very naif approach)

reorganise code

Rollback support

move extensions in a hgext directory

clone support

Change test output again (get a better distinction between rev number and hash to detect hidden changeset)

update README

Don't overwrite non local repo.

Do not propagate obsolete changeset

include hash in test.

Add pushkey support for pull and push

more comment

Make rebase set-obsolete relation

Do not hide current and bookmarked