Improve import support

[davesmith00000]

Currently to use imported methods, you have to do this:

import ultraviolet.sdf.circle
// import ultraviolet.sdf.* // works too.

def proxy: (vec2, Float) => Float = (p, r) => circle(p, r)

proxy(vec2(0.5f), 1.5f)

The proxy is annoying, but a separate issue.

What I'd like is to be able to do both:

ultraviolet.sdf.circle(p, r)

and

import ultraviolet

sdf.circle(p, r)