histedit: add forceother constraint For the future 'base' action in histedit we need a verification constraint which will not allow using this action with changes that are currently edited.

histedit: make verification configurable Before we can add a 'base' action to histedit need to change verification so that action can specify which steps of verification should run for it. Also it's everything we need for the exec and stop actions implementation. I thought about baking verification into each histedit action (so each of them is responsible for verifying its constraints) but it felt wrong because: - every action would need to know its context (eg. the list of all other actions) - a lot of duplicated work will be added - each action will iterate through all others - the steps of the verification would need to be extracted and named anyway in order to be reused The verifyrules function grows too big now. I plan to refator it in one of the next series.

paper: show current revision on file log page Most of the pages in paper (and coal) style show the current revision and its branch, tags and bookmarks. Let's also show all this on file log page.

merge.applyupdates: extend action queues with ones returned from mergestate These queues will always be empty at the moment -- we're going to fill them up in upcoming patches.

mergestate: add a method to compute actions to perform on dirstate We're going to use this to extend the action lists in merge.applyupdates. The somewhat funky return value is to make passing this dict directly into recordactions easier. We're going to exploit that in an upcoming patch.

merge.applyupdates: use counters from mergestate This eliminates a whole bunch of duplicate code and allows us to update the removed count for change/delete conflicts where the delete action was chosen.

mergestate: add a function to return the number of unresolved files Note that unlike the other functions, this is based on the persistent mergestate.