Merge pull request boot2docker#1250 from tianon/commit-rc-bumps

Update to 17.04.0-ce-rc2 (and update Dockerfile to switch to the "test" channel automatically for -rc releases)

Swap channel to stable

Update kernel to 4.4.55

Update VBox additions to 5.1.18

Merge pull request boot2docker#1241 from nathanleclaire/bins_bins_bin…

…s_bins_bins_bins_bins

Update boot2docker build to get binaries from new URL

Update AUFS to v4.4-20170220

Update to 1.13.1

Update to kernel 4.4.47, AUFS v4.4-20170206, aufs-util aufs4.1-20170206

Update kernel to v4.4.45, AUFS to v4.4-20170130, aufs-utils to aufs4.…

…1-20170130

Update to 1.13.0