[PATCH 0 of 3] Gradual performance improvements for Hg on Win32

[Petr Kodl]

This is a series of patches tageting Hg performance on large source trees. 
The first patch has been published before - it implements equivalent of osutil.c for Win32 
Second patch addresses problems reported is tracker as 1286 
The last patch attempts to further consolidate ops on large tress by minimizing # of spread lstat operations 

With all three patches applied I rarely get a response time over 1s on trees with ~1200 directories and ~39000 files. 
This is around 2-4x improvement over 1.0.2 release version 

The last patch is the most questionable one - it should improve performance (and it does in all cases I tested), but the behavior 
will be probably OS/source tree structure specific