move bus stop icon to SVG

[nebulon42]

Implements part of #1165.
Size now remains unchanged after #1478 (comment).

before

after

[mboeringa]

Looks nice. I was fine with the bigger version too, but this is OK. The bus now also looks a bit more modern compared to the old "before" one, which more looks like a '50s bus.

[matkoniecz]

It is amazing how quickly and how much I started hating the old bus icon. A great improvement, thanks!

[nebulon42]

Thanks too! :)

[daganzdaanda]

Thanks, also from me. The old bus looks ancient, maybe the icon was made in the sixties ;-)

[kocio-pl]

And the old one was sooo blurry. =}