Add hg-relink script to contrib

merge with crew-stable

debugsetparents: wlock the repo before updating the dirstate

avoid _wsgioutputfile <-> _wsgirequest circular reference We use the _wsgirequest object itself as the output file object. To avoid a "self.out = self" which would create another circular reference, we make the "out" attribute a trivial property.

avoid wsgiapplication <-> MercurialHTTPServer circular reference

hgwebdir: break templater -> templater circular reference This is essentially another instance of the same problem fixed by the parent changeset. See its commit message for the details.

hgweb: break templater -> templater circular reference The problem were some functions passed in the "defaults" argument during the templater creation which use "self.t" directly. This creates the cycle: hgweb object -> templater object -> defaults dict -> footer function -> hgweb object Instead of completely avoding the cycle, we break it after using the templater.