Swap windows

[azarakovskiy]

A function that swaps two windows.

The issue i'm solving is the following:

• My screen on the left is big, and I don't like turning my head to the left :D
• I have two windows there, one of them is usually in my focus, and then another one. Like a debug panel and a console.

Implementation:

• Select a window and hit mesh+s, save the window ID
• Select another window. mesh+s will now swap it with the first one
• Hitting mesh+s on the first window, removes the saved ID and resets the swapping pair

[peterklijn]

Hey @azarakovskiy,

Thanks for the PR. In general I like the idea of being able to swap two windows, but I find the usage a bit complicated.
I installed it locally, but don't find the usage very intuitive. The showing of letters is pretty cool, but I struggled to select two windows, as well as to un-assign one.

I wonder if there's a more intuitive / simpler way to approach this. One way to validate it is to write documentation on how to use the feature, I think the current implementation requires quite some explanation for others to understand.

I'll give it some thought, but feel free to come up with a simpler approach as well.

Apart from that:

• I prefer all additional features outside of the standard ShiftIt features to be opt-in (like this one)
• Add some tests to validate the code of the feature
• Update the readme documentation so others can use it too.

But I would park these until after a more intuitive approach is found :)