A bunch of small updates

Hi Frank
You may choose to skip the 20s startup delay, but I suspect that in some cases softether doesn't setup properly (when starting up a new server in CoreOS) (I do have a network dependency as well)

As per the dockerfile: A little less clean, but 2/3 of the image size.

PS, is there a reason for Ubuntu and not Debian? That could shave another 120mb.

Cheers