ports tree tagging again

[Andrew Pantyukhin]

When/if we get a new VCS, where branching is not as painful
as it is now, I expect it to be used extensively by developers.

Projects can be then brought back into our main repo from
marcuscom, p4 and other local repos. We often work on some
things together and/or from multiple locations. It feels so
awkward to send patches in email attachments or uploading
them somewhere.

Moreover, with a new VCS, I expect a possibility for maintainers
to gain commit rights to some separate branches. Committers
may then easily review and merge changes to the trunk.