Add CSS class name prefix to prevent conflicting styles when using SVG mode

[glennsayers]

Hi @KilianB

Thanks for maintaining this fork - it's been of great use in one of my projects.

I have a use case where I need multiple SVG based QR codes on one page. Currently, due to the inline SVG styles not being uniquely named, I cannot have these QR codes be different colours.
I've added a row of SVG codes to the bottom of demo page to show this - note how they all inherit the colour of the last QR code:

To fix this, I've created a small function that will generate a random character string, and prefix this to the CSS classes on a per QR code basis. This makes the styles unique and prevents clashes.
See the same demo with this change added:

Thanks!

[KilianB]

Thank you. I'll check it out on Monday and will merge it

[vpenyazkov]

@KilianB do you still maintain this repo?

[JeneaVranceanu]

@KilianB do you still maintain this repo?

@KilianB Wondering the same.
I'm working on my own updated fork. I think it would be reasonable if I open a PR instead of creating a "new" package.