Allow alternative shapes for node and tips

[rambaut]

Lots of possibilities - triangles, stars, polygons, emojis?

[Eddylusamaki]

some examples of shapes are here :
https://www.phylocanvas.gl/docs/constants.html#emptyarray
Beyound that, Emojis (of some common animals like human, bats, rodents, squirrels, monkeys) would be fun as well if possible.