[VOTE] XML formatting

Hi folks:

So although we have project-wide Java formatting conventions, I note
that we don't have any for XML files - in particular for poms.

Can we settle on indent size for XML, and then I'll go and reformat all
the poms to look clean?  Please VOTE for your desired indent spacing as
follows :

[ ] 2 spaces
[ ] 4 spaces

Thanks,
--Glen