Write tty friendly pullstrea progress

This is build ontop of PR #3 please merge that first.

This commit:
 1. Uses `\r\n` for proper terminal support... We could make this optionally depend on the `tty` value in `_createConfig`, it would take a few hacks... but it's doable.
 2. It uses simple timestamps to add image layer download time to the log.

Ideally, we should export the pull method. So that we can get the total layer download time in docker-worker and include it as result - perhaps `setupTime` could be a formalized entry in `result.json`. But this is also pretty good, and will allow us to look it up, which is a lot better than nothing.