Feature Request: Add "stickers" or symbols (other than emoji, which are currently supported)

[shannonturner]

Right now you can add emoji to a station name, but what if there was a bank of "stickers" or symbols that could be added?

These could be added to the canvas via .drawImage() (https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/drawImage), and inclusion in SVGs would be trivial (assuming the stickers/symbols were SVGs as well).

These could be especially useful for insets, legends, the Metro "M", etc.

[shannonturner]

Suggestion from Youtube:

Add an option that allows people to add symbols to the train station (bus,plane,cable car,boat ect for bus connection,airport connections ect,maybe even a symbol for peak or limited service stations also for stadium or racecourse station also staffed and unstaffed,accessible,non accessible ect)