Add windows and tabs

[guysherman]

Adding New Windows

Some thoughts on creating new windows and tabs

• Probably want a separate keybinding for window and tabs
• Need sensible decisions about where to put the newly created thing so that
  you don't have to navigate to the right place first, ie will adding a new
  window add it immediately after the current one, or as the last window in the
  tab? Will adding a new tab add it after the current one or as the last one. If
  you're on a tab does adding a window insert it as the first one?

Maybe:

• n: append new window after current
• N: append new window as last
• c-n: insert new window before current
• c-N: insert new window as first
• If on a tab, assume 'current' is previously active window in active tab
• If on an OS window, assume 'current' as previously active window in active tab

It is unclear how this will actually work in kitty, it depends on how the overlay mode is counted.

Likely steps:

2. Set up keybindgs
3. Create addWindow function
4. Populate the various options

[guysherman]

Not actually sure this is necessary, since kitty has good keybindings for this anyway, will reconsider post 1.0.0 release.