[plt-dev] Domain changes

I've changed all the web pages on champlain (bugs, git, svn, docs,
download, internal, etc) to use "racket-lang.org" by default.  They
all have the "plt-scheme.org" addresses as aliases, so existing URLs
will continue working.  (Once the web pages are all revised, the
download web pages will be separated again, the old pages will stay as
is with an "obsolete" label.)

In addition, I've change everything in gnats to use racket-lang.org
now.

(And also the machine is now in its temporary location, so it has a
different IP address, but as I thought, this shouldn't be visible
modulo DNS propagation delays.)

-- 
          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
                    http://barzilay.org/                   Maze is Life!