Windows installer for bzr 2.5.1

[Martin Packman]

So, that took me from shortly after I posted that till the
announcement email, or about an hour and a half. A fair bit of that is
waiting for things to happen and I was arranging things for tomorrow
at the same time.

Some of the pain was self inflicted:
* Had trouble finding cunningly disguised piece of paper with password on
* Forgot to allow access to my wsgi upload script for the ec2 instance again

My connection is slow, so getting the installers down to here then up
to launchpad just takes a while.

I'd forgotten the details of the regression I'd introduced trying to
work around the setuptools dulwich problem, or whether I'd left it in
a good or broken state. Was expecting it to break the build or git
support, and do something about it if so. In fact, it completely
breaks selftest, which I didn't check. Should have just backed out the
change and done the workaround with a patched dulwich branch from the
start. That will want fixing next time around:

<https://bugs.launchpad.net/bzr-windows-installers/+bug/968189>

I'll get round to committing my instructions for doing this somewhere,
needing access to a particular ec2 account is still something of a
blocker for anyone else picking this up however.

Martin