Allow multiple windows

[Splitwirez]

Jaya needs to allow multiple windows to coexist. I'm not convinced that separate processes for each is the best approach, partly because #33 means we'd need to allow the user to 'drag' tabs between separate windows.

[waliarubal]

So this is something apart from Tabs? I was under an impression to make the app single process for now.

[Splitwirez]

I think using a single process for all active Jaya windows would be a good idea, yes.

To clarify what I was referring to...in Firefox, for example, you can drag tabs from one window to a new or existing window, like this: https://www.youtube.com/watch?v=yecyFamSh6c