dropping support for osx 10.4 x86

[Graham Percival]

lilypad will not work on osx 10.4 x86.  It works on 10.4 ppc.  I
do not consider bugs in osx-10.4 x86 to be release-critical; they
should be filed as normal type-build bugs.  Somebody may want to
update the download page accordingly to avoid giving users the
wrong impression.

If somebody can make 10.4-x86 work, then it would be great to
officially support it again in the future.  However, I think
that's too far away; delaying 2.16.0 for that doesn't make sense.

- Graham