Save zoom and focused window from layout so that it can be restored

[Andrew-Collins]

Hi,

This PR is to support restoring layouts with with zoom and focus.
Related issues:

• style = "restore" does not restore <C-w>z iamb#247
• Restarting after quitting with tabs doesn't restore focus iamb#250

A new struct WindowLayoutStorage has been created to store: the windows layout, which window is in focus, and if the focused window is zoomed.

TabLayoutDescription has been updated to hold this struct in place of WindowLayoutStorage as well as store the currently selected tab.

I am not set on the name WindowLayoutStorage; would you be open to naming it TabLayoutDescription, and rename TablayoutDescription to AppLayoutDescription or something similar?

This seems more logical to me as currently TabLayoutDescription does not hold the layout of a tab, but rather the layout of the top level application.

Keen to hear your thoughts. :)

[ulyssa]

Thank you for doing this, this is a really great addition! 🥳 I'll make sure to pull it into iamb so those issues can be resolved.

I am not set on the name WindowLayoutStorage; would you be open to naming it TabLayoutDescription, and rename TablayoutDescription to AppLayoutDescription or something similar?

This seems more logical to me as currently TabLayoutDescription does not hold the layout of a tab, but rather the layout of the top level application.

I think you're right that having it be a singular Tab is not quite right, but I like having Tab in the name for the thing that actually knows about tabs, so I've renamed it to TabbedLayoutDescription. I also renamed WindowLayoutStorage to WindowLayoutRoot so that it mirrors the tree structure in its naming.