Merge pull request #36 from mavenugo/master

Fixes #35
Merge pull request #38 from mavenugo/master

Fixes #37 and #33
Merge pull request #39 from mavenugo/master

Updated README
Merge pull request #40 from mavenugo/master

Removed checks for Docker login
Updated README for a corner case where docker fails to start agent

Signed-off-by: Madhu Venugopal <madhu@socketplane.io>