Add new module: X.L.CircleEx: advanced version of Circle layout

[portnov]

Description

X.L.Circle layout is somewhat nice, but it does not provide much possibilities for customization. This adds a new module, X.L.CircleEx, which is similar to X.L.Circle, but has some new features:

• Number of "master" windows can be adjusted. For example, with 0 master windows, all windows go in a circle, nothing in the center.
• It's possible to configure sizes of master window and slave window (as a portion of screen size).
• Size of each next slave window is slightly less than size of previous (configurable)
• It's possible to rotate whole setup clockwise / counterclockwise. For example, by default first slave window opens near right edge of the screen, but I like it to open near left top corner.

Checklist

• [x] I've read CONTRIBUTING.md

• [x] I've done extensive manual testing by using it for a month :)

• [x] I updated the CHANGES.md file

[portnov]

(i) implement that in terms of this new module, and (ii) perhaps deprecate X.L.Circle (if that's desired)?

Ok. For (i), I added a variant of default settings which mimics X.L.Circle's hardcoded settings.

[portnov]

@TheMC47

[portnov]

@slotThe ok, importing (:%) from GHC.Real did the trick. I'm not very happy with exporting data constructor, because it will complicate things if / when it will be required to add fields to data type. But probably you're right and not having a duplicate of logic overweights that potential problem.

Now, when I deprecated X.L.Circle module, I see some number of deprecation warnings, since it was used in several places. I think I should also replace Circle with CircleEx in these places.

[slotThe]

Now, when I deprecated X.L.Circle module, I see some number of deprecation warnings, since it was used in several places. I think I should also replace Circle with CircleEx in these places.

Sounds good :+1:

[portnov]

Done. Please review.

[slotThe]

Thanks! (I just pushed some doc fixes)