Add version information for components we depend on.

Sample output:
Version: {KernelVersion:3.11.0-17-generic ContainerOsVersion:Ubuntu 14.04 LTS DockerVersion:1.0.0}

This is the start of the debug page. Still need to add cgroup and namespaces status plus the final debug page.
@monnand Not particularly attached to the outer index. It feels safer to fill up the string serially without depending on the index from for loop. It doesn't matter in this case though.