[MERGE] win32-specific fixes for selftest and bzrlib

[Vincent Ladeuil]

Vincent Ladeuil has voted comment.
Status is now: Semi-approved
Comment:
I think some of this fixes apply to OSX too.
Some are trivial too.
May be you can make several submissions so that this patch  can be 
merged quicker.

I'd recommand three:
- one for msgeditor,
- one for multiparent,
- one for the rest.

Note that the part related to test_commit_builder have already been 
merged.

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C46E14685.5080805%40ukr.net%3E