[MERGE] Implement xml8 serializer

[Harald Meland]

[Aaron Bentley]

> Hi all,
>
> This patch implements the xml8 serializer which will be used by the
> upcoming pack-1.4 format.

I haven't reviewed the code, just took a quick look at the patch --
and I am somewhat confused by the add/remove/rename file operations it
claims to do:

> === added file 'bzrlib/xml5.py'
> === added file 'bzrlib/xml6.py'
> === removed file 'bzrlib/xml6.py'
> === renamed file 'bzrlib/xml5.py' => 'bzrlib/xml8.py'

You appear to change the file id of xml6.py; is that by intention?
Also, by renaming xml5.py to xml8.py, any changes other people might
have for xml5.py will now be attempted merged into xml8.py; is that by
intention?
-- 
Harald