Add flag to auto-ssh into a newly created (single) VM

[whopper]

99.9% of the time that I'm grabbing a VM from the pooler, I want to SSH into it. With my janky old vmpooler helper, I did this with a flag, i.e:

vmify -o ubuntu -v 1604 -c

... where the -c flag immediately SSH'd me into the ubuntu 1604 box that it grabbed. This saves the trouble of having to copy the name of the VM I just created and enter another command to remote into it.

This is a feature request (and reminder for me to PR it someday) for that flag. It'd have to only work when grabbing a single VM, and otherwise probably warn and ignore the flag.

[briancain]

@whopper I just cut a release with this feature. See the referenced commit for more info 👍

[whopper]

@briancain whoa! Thanks! :D