It's convenient for old releases to be available indefinitely so that
deployment scripts can retrieve a particular qualified version. This
won't affect the disk space requirements of the repository, since the
old packages will be in the Git history anyhow.
Move packages to a subdirectory of the site root to avoid causing
permanent clutter.
{Tar,zip}balls now have the form openseadragon-bin-0.9.125.{tar.gz,zip},
containing a directory openseadragon-bin-0.9.125.
Including the project's version number makes it easy to determine the
version of a random release sitting around a filesystem, and ensures
that unpacking a tarball won't overwrite another unpacked tarball or
write into a checked-out repo.
Adding -bin distinguishes the packages from source tarballs, which are
conventionally <project>-<version>.{tar.gz,zip}.
Tar files are conventionally compressed, often with gzip. xz would be
better but is not as universally supported; in particular,
grunt-contrib-compress doesn't support it.
