cmdutil: implemented new lazy increasingwindows
Now log can work in a lazy way and get results as soon as they are processed.
Performance Benchmarking:
$ time hg log -l1 -qr "branch(default)"
0:
9117c6561b0b
real 0m2.303s
user 0m2.252s
sys 0m0.048s
$ time ./hg log -l1 -qr "branch(default)"
0:
9117c6561b0b
real 0m0.238s
user 0m0.199s
sys 0m0.037s
(binary:application/octet-stream)