Big Changes

Support for Authenticated (User/Pass) Docker Repositories in native garden-shed rootfs fetcher! Woop!

Little Changes and Fixes

RunC output is now streamed to the main garden log rather than collected after execution has finished. This enables better diagnostics for cases where runc hangs or deadlocks
Fixed a regressed that made /etc/hosts and /etc/resolv.conf not writable by root in the container
max_containers property is now enforced rather than just being reported in client.Capacity()
Changed image_plugin api to allow the plugin to return JSON in order to better support rootless containers using overlayfs (the image plugin API is still experimental and subject to change)