[Rivet] Rivet 1.8.4 nearly ready / OS X Mavericks

[David Grellscheid]

Hi Andy,

> One thing occurs to me which we should test before releasing: making
> sure that the AIDA branch is compatible with OS X Mavericks. 

The one-line fix in the main code works, but Swig has a few more of them
in rivet/rivetwrap_wrap.cc. I don't know if their origin can be fixed
without fixing swig.

  David