[PATCH] auto rename: best matches and speed improvements UPDATE1

[Herbert Griebel]

I could again improve the speed by up to 40%
in the mid range by using histograms in the
deferred comparisons, making all checks lazy.
The new patch is in the next mail.


Updated performance figures:

Command used: hg addremove -n -sX
Measurements are done with disk cash to get stable times,
on a Laptop with Centrino Duo, 2GHz, 2GB RAM.

Working dir:
1055 removed, 1234 added, lots of changes in about 30% of the files,
roughly 80% moves and 20% renames

similarity   time old	time new
1%           82.0s	82.0s
50%          41.5s	25.9s
60%          36.6s	20.8s
80%          26.4s	16.0s
90%          21.3s	15.0s
100%         12.0s	12.6s
The old version took 59min, independent of the similarity.


Regards,
Herbert