Updating `sumstatsvector` in mac bin directory.

Replacing `sumstatsvector` in mac bin with universal (compiled for archs
ppc, i386, and x86_64) statically-linked binaries built under Darwin
8.11.1 on a mac running osx 10.4.11 (montgomery). `sumstatsvector` is
updated to allow longer loci (more segregating site per locus).