Build instructions mention non-existent `configure` script about pixz

[cicku]

homebrew might use the wrong tarball? Release tarballs contain configure scripts, whereas the source tarballs don't contain. You need to manually run autoreconf.

[wookietreiber]

I have added the proper release tarballs to the release page, i.e. you should not use the source code tarballs, but the ones called pixz-<version>.*. I apologize for not doing that in the first place.

[justinmayer]

Thanks for the proper tarballs, Christian. After doing some testing on Mac OS X 10.10, I noticed that some of the changes in 1.0.3 required some modifications to the Homebrew formula. I made what I believe are the appropriate adjustments and have submitted a pull request for 1.0.3 to the Homebrew repository.

[wookietreiber]

@justinmayer Is autoconf really required? As far as I know, it should not be, because the configure script is already generated in the release tarball, and that is what autoconf does, generate configure.

[justinmayer]

You are correct. I added that back before the tarball had been fixed to include the `configure` script. Will update the pull request accordingly.