DeviantArt Anti Janky av minipixiv.ext

Scrolling on DA is choppy and unresponsive. This addon tries to improve that.

- v1 just removes some visual fx, to improve browser performance.
- v2 will disable lazy-image-loading that adds to the jankiness (to do).

Works better when coupled with some ad blocker.
Ads and trackers bring a lot of javascript, which is the janky lord.

Also, artwork dimensions were limited by width+height, making them small to fit the screen.
Now they get limited by width only, so they are naturally bigger and better to see.
Might add an option later on to disable that.