Adds keycaps for Splitting windows

These are the settings from the old key mapping.  it is similar to the shift-it keybindings with the addition of the shift key.

**smash + up** for split vertically
**smash + down** for split horizontally
**smash + left/right** for move to opposite tab group
where *smash* = **Cmd + Opt +Ctrl + Shift**

I don't think we should bind ctrl+s to anything but save as Windows and other os's consider that to be the save key, it's kind of like binding ctrl+q or w where the key already contains a lot of meaning.