Margin not working properly

[Psycarlo]

Reproduce steps:

1. https://qr-code-styling.com/
2. Width: 200
3. Height: 200
4. Change margin one by one

It only changes around every 10-15 points.

[Psycarlo]

Maybe we could remove margin entirely so users can handle that on a outside div? So the canvas would always present the the qrcode with no margin, which means all outer points touching the border.

Maybe only to this as default because users might want margin (those who are going to download it).