#52 open shell command outputs in new buffer

In acme you can run commands and have their output be displayed in a new buffer. This idea could be nice and I've had some situations when I'd like to see the output and potentially copy the output for some purpose instead of suspending ait and then resuming it or using another tab.

Not sure where this fits into the timeline.

I'm thinking that this would actually be kinda nice and not that difficult. I'm not 100% sure what the benefit of doing this is or how it will be done, yet.

Moving this out of 1.10 milestone because I don't really need this