Add image update capability

[thenewwazoo]

As a system owner, I want to update the running image in situ, so I can perform updates without having to burn and ship an SD card.

At present, updating the running image requires writing an SD card and physically inserting it into the CuBox. The swupdate software and the corresponding meta-swupdate layer look like good options for doing in-place image updates.

[gil0109]

You may want to look at mender.io as well.