gavin -> new maintainer

[Karl Berry]

As some people here already know, Gavin (Smith) has been doing a
tremendous amount of work with Texinfo for a while, especially the Info
viewer, but in plenty of other areas too.  I've asked him to become the
new principal maintainer of Texinfo, and he's kindly accepted.  Please
welcome and support him!

(I'll still be around, especially for texinfo.tex, but no longer feel I
can take the lead on maintainer issues.)

Happy hacking to all,
Karl