[tlbuild] rebuilding mpost + asy needed

[Karl Berry]

1) Taco has checked in a fix to metapost so that foo.bar.mp will again
   output foo.bar.NNN, as it should.

2) John (Bowman) has released version 1.88 of Asymptote that should
   build without OpenGL (it did for me).
   
2a) The svn-version-number mismatch with asy that has been noted is
    because John also introduced a new feature of including the svn
    revision for his own development builds.
    
    The simplest workaround for us is to mv our .svn directory aside
    before doing the configure&&make, and then mv it back afterwards.  I
    updated http://tug.org/texlive/build.html#asymptote accordinly.
    
    I have checked in the support files for 1.88.

Please, everyone, do the usual ASAP.

Thanks,
karl

P.S. I really do not want to build anything again this year.