Options to save the world

[tjwatson]

Currently save the world only takes a single argument to specify the directory to save the dumped image. I imagine we will need more flexibility in configuring the calls to save the world. For example, my usage scenario will want to terminate the process as soon as the dump is made. This will ensure the process does not make modifications post dump that could inhibit a successful restore of the process later.

I would suggest adding a simple boolean option for this one option (leaveRunning). But perhaps something more advanced is needed to hold the various CRIU options.

[chflood]

These are all things that were put on the "deal with later" list. I'm happy to add a boolean for leaveRunning to the call.