Change comment icon to vector art

[benloh]

@jdanish Actually this is already a svg. But we can probably refine the shape a little more so that the little tail is more visible

[jdanish]

Oh I thought you had said it wasn't and that was why it was a bit pixelated. I think leave it then.

[benloh]

It probably looks pixelated because I have a stroke around it to offset it from colored nodes, otherwise it gets a little lost. We can tweak it to look a little better.

[jdanish]

Ok but let's call that low priority I think?

[benloh]

note to self: overflow: hidden might be cutting off the edges of the stroke.