revset: added lazyset implementation to checkstatus This improves the performance of the revsets 'adds' 'modifies' and 'removes' Performance benchmarking: $ time hg log -qr "first(adds(README))" 0:9117c6561b0b real 0m2.279s user 0m2.222s sys 0m0.053s $ time ./hg log -qr "first(adds(README))" 0:9117c6561b0b real 0m0.172s user 0m0.131s sys 0m0.041s $ time hg log -qr "first(modifies(README))" 1:273ce12ad8f1 real 0m2.292s user 0m2.227s sys 0m0.061s $ time ./hg log -qr "first(modifies(README))" 1:273ce12ad8f1 real 0m0.178s user 0m0.130s sys 0m0.038s $ time hg log -qr "first(removes(README))" 2379:e90cff87f871 real 0m2.297s user 0m2.235s sys 0m0.058s $ time ./hg log -qr "first(removes(README))" 2379:e90cff87f871 real 0m0.975s user 0m0.797s sys 0m0.056s