Add support for Microsoft VS Code icons

[grolongo]

following #27

[rougier]

Thanks !

[rougier]

By the way, I've since discovered: https://pictogrammers.com/

[grolongo]

Thanks !

Thanks to you.

By the way, I've since discovered: https://pictogrammers.com/

I just checked and it's the whole set of Material icons.
svg-lib already provides them and I don't think there is any difference:

("material" .
     "https://raw.githubusercontent.com/Templarian/MaterialDesign/master/svg/%s.svg")