phases: define an official tuple of mutable phases Such tuple was already manually defined in a couple of place. Having an official definition makes it easy to introduce of new phases.

repoview: use 'phasecache.getrevset' when computing 'unserved' filter This reuses a precomputed set, being much faster than manual iteration. Computing the "unserved" filter speed up by 55%. before: wall 0.014671 comb 0.020000 user 0.020000 sys 0.000000 (best of 180) after: wall 0.006623 comb 0.010000 user 0.010000 sys 0.000000 (best of 401) The "unserved" filter is used to restrict the revisions client can pull from a server. (eg: secret changesets)