using latest default image version for linux and macOS in travis build
using latest default image version for linux and macOS in travis build

gubatron/frostwire-jlibtorrent,aldenml/frostwire-jlibtorrent,gubatron/frostwire-jlibtorrent,frostwire/frostwire-jlibtorrent,aldenml/frostwire-jlibtorrent,aldenml/frostwire-jlibtorrent,frostwire/frostwire-jlibtorrent,gubatron/frostwire-jlibtorrent,frostwire/frostwire-jlibtorrent