candy cane swapped for non-repeating vertical bands

[HCAWN]

I love being able to read the titles of events in my calendar now but the striped angled background can be a bit distracting. I've changed the background styling to look more like an unmodified calendar:

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To

[HCAWN]

Events not responded to or declined now appear striped, allowing even title to be read (rather than white background with border)

Also added Manifest V3 support

[HCAWN]

Some ui fixes (white text not coloured)
I've made the original events opacity:0 now instead of visibility: hidden and repositioned them to align with the evenly distributed gradient so users can click on the original calendar events. This fixes issue 86
also issue 78 styling fixed with previous commit
@zlanich @danyal

[eoinbutler]

I really like the striped candy-cane over the striped vertical style. I would suggest making this an option so as to maintain reverse compatibility.

[HCAWN]

@eoinbutler
Good idea, choice is always better, I've made a popup with that toggle and also set the stage for more options to be put into the popup:

HCAWN#4

[michaelblyons]

Do you want issue reports? GitHub disables the issue tracker on forks by default, but you can turn it back on.

[HCAWN]

@michaelblyons I've just enabled, please fire away!
With no word from Amy, I'm going to stop pushing to this PR and keep further updates on my fork (and my chrome extension link)