waf: building tely+texi, no pictures

[Graham Percival]

The current state of waf is that we can't copy or link filenames that
go to the same directory (modulo srcdir/blddir).  Yes, "cp ${SRC}
${TGT}"... where SRC is in the srcdir, and TGT is in the blddir...
fails.  If you want to see the error, check out dev/gperciva, edit
Documentation/wscript_build, and uncomment the pictures subdir bit.

There's a message on the waf list about this problem, from July 2008.
There's a note that it's a known limitation that fixing it is on the
TODO list.
http://groups.google.co.uk/group/waf-users/browse_thread/thread/e4470c6d5268cb6a/7880b48830b72527?lnk=gst&q=copy#7880b48830b72527

(I'm not blaming other projects for not resolving issues, but it
*does* still cast serious doubts as to whether we want waf)

On the plus side, at least the two -init.pl files are almost merged in
this branch.  I'll look at bringing that work into master in the near
future.

Cheers,
- Graham