[MERGE] install plugin l10n files with Windows binaries.

[Mark Hammond]

> The patch seems fine as is, though I have a few questions:
> 1) What is being packaged by installing it in 'bzrlib/plugins' versus
> stuff like TBZR being installed using env options.

I'm not 100% sure what you are asking, but the build process assumes that
plugins have been "fully installed" (ie, including extra data files, such as
these l10ns) in the ./bzrlib/plugins directory.  Tortoise isn't a plugin, so
we can't find it under the bzr tree, so an env var is used.

> 2) How do you make sure to bundle the correct plugins? IIRC 1.6rc? had
> bzr-svn bundled, but the final 1.6-final did not. I'm getting the
> feeling we need a bit more explicitly defined process, rather than just
> happening to bundle what is directly found.

Agreed 100% - I also think we should enforce that the list of 'missing'
modules is empty at the end of the process, and I previously made some moves
towards that.  However, the overhead of getting code landed makes me fear
that even a theoretically simple change like a nominated list of included
plugins will involve several "tweak" round-trips with the final few related
to grammar in the comments, making the status-quo sound attractive :)  I
agree such changes would be good and would be happy to review any.
 
Cheers,

Mark