Adds surface focusing mode

[al-caveman]

- Adds 'focus estranged left|right|up|down|next|prev'
- Modifies sibling focus from: 'focus next|prev sibling' into:
'focus sibling next|prev' for consistency with the estranged one.

Fixes #3738

[Airblader]

I'm a bit constrained on time and I think @orestisfl understands this code the best at the moment anyway, perhaps he can take a look and help you further on this for now.

My only comment right now is that we'll need to squash the commits into one proper commit in the end, but of course there's many other things to be done as well (userguide, tests). :-) I'm not yet sure about the "lazy" (for the record, I dislike "estranged" even more). We should try to think of a more descriptive name.

[al-caveman]

And I just did my 1st github squash ever 😀. I don't know for sure, but by the looks of it, my heart says that something is not right.

[Airblader]

my heart says that something is not right.

Yeah, it is definitely not correct at the moment. :-/

[al-caveman]

Fixed commit. Now my PR looks as if I always was a very smart guy.

I guess the trick is to always forcefully push lies to my github fork? I.e. 1st rewrite history to look smart, then push such lie by push -f?

[Airblader]

Yes, squashing rewrites the history of your feature branch and therefore requires rewriting the history. :-)

[al-caveman]

now i no longer touch the implementation of cmd_focus_sibling, nor alter its syntax. i only extended cmd_focus_direction to have an extra argument mode that is either normal or surface. i.e. it adds this:

focus left|right|up|down|next|prev surface

o, and, instead of calling the new mode lazy or estranged, i called it surface - thoughts? its naming comes from the imagination: it lets you move around the tiles as if you are a bird flying over the surface (visible tiles), without causing to unhide any hidden tiles.

synopsis: this feature will allow navigating throughout stacked/tabbed/normal windows without getting stuck in tab/stack swamps (more info on this in #3738), without even needing mod+a to get out of the swamp. it noticeably enhances i3's usability.

a neat side effect: once coupled with focus next|prev [sibling], we can effectively configure i3 such that tabs vs. stacks is only a matter of appearance. e.g. we can consider stacks/tabs to be (say) themes of tabs, so users shuffle them accordingly to (say) minimize pixel wastage.

[Airblader]

I'm OK with the complexity of the change, but haven't reviewed it yet. I'm not too happy with the naming yet, though. To be continued. :)

[al-caveman]

how about visible or visible-only (or only-visible.. dunno which one is more english (or should it be plural? e.g. visibles? visibles-only? only-visibles))?

[stapelberg]

Closing this PR as the author is banned from all i3 community spaces after interactions such as (but not limited to) https://www.freelists.org/post/i3-discuss/squigz-abusing-op-power-in-i3-i3offtopic