Investigate dropping screen requirement

[rwilliams]

See if tmux gives a smoother experience than the current screen implementation.

[rwilliams]

Maybe we can dump screen altogether. From Jan

By the way, I remember that I made these 2 pull requests to jruby in relation to theine:
jruby/jruby#3492
jruby/jruby#3494

I don't remember exactly why I needed that, but I think it was for better support of console/irb through sockets. I think I wanted to copy how some of the ruby mri preloaders were doing it (spring or zeus). I think the pull requests were merged into jruby after I stopped working on theine, so now that they are merged it could be possible to use these features.
I think I switched to using screen (mrbrdo@f966fe8) because of the lack of these features in JRuby at that time.

[rwilliams]

It looks like these changes can be backported into Theine to remove the screen requirement.
rails/spring#449