pkgtools/revbump re-written to be easier to use

[Thomas Klausner <wiz%NetBSD.org@localhost>]

Hi!

I've just finished rewriting pkgtools/revbump, the tool to recursively
bump PKGREVISIONs and BUILDLINK_ABI_DEPENDS when shared library major
versions change, as 'revbump.py' in Python.

It now does everything in one step, the usage example is now:

           revbump.py category/package
           # check for problems
           cvs diff $(cat commitlist) | less
           # if the diff is ok
           cvs commit $(cat commitlist)
           rm commitlist

Please give it a try and report any problems.

The old perl scripts are still available in the package; I'll remove
them once the new version has had some more testing.

Cheers
 Thomas