Add new background related option: background-clip about nimble-builder

I just played with it a little. This is interesting but I didn't really see a use case justifying an addition to Nimble.
So I googled an found this https://css-tricks.com/the-backgound-clip-property-and-use-cases/
And now I need to go through this huuuuge post to see if we can find a use case.

If you don't mind let's put that on hold for the moment, and see if our future Nimble users could find a use case for us :)

[eri-trabiccolo]

Ahah.
Well yeah, given the current hmtl structure of nimble it might be not that useful I agree. Might stay as a 'goodie' to me. E.g. imagine a dashed border + background, you might not want the background below the border (choose padding box). Or, say you apply a background to the column level (which has right/left padding by default) and you want to apply it only to the inner content (padding excluded then), you can choose the content t-box.
That's all.

p.s.
FYI when I tested this with google-chrome inspector, using the "live" CSS, changing this property I couldn't really see any difference if not after changing the background property again.

ok I see. Let's keep it as a goodie !