[Improvement] - Add Retina support

[gyli]

I don't know where those icons are from and if it's feasible. But I would love to see 32*32 favicons for Retina support on high resolution screens.

[JB4GDI]

This is a great catch! Most of icons come from a giant AWS sprite sheet, but it's a very manual process, and some of the ones that don't have icons (billing / console) I've made my own icons for. That said, I'll see if I can make this happen! I imagine the 16x16 icons look bad and I can see 32x32 becoming a standard down the line.