Add a real simple example

[HugoGresse]

Hi there,

This seems like an issue that does not respect the authors or took care of reading the documentation.
I'm new to Three js, and wanted to just perform simple CSG operation, however, the only documented and with working examples library I've found is this one. But it's not the easiest to get started.

I've look at the simple.js example, but due to the extensive controls and choices and materials, I'm pretty lost.

It could be great to have a more static example, like substracting a circle from a rectangle sort of thing...

Let me know what you think, I can also do a quick PR for that.

[hrgdavor]

I retract my comment due to project owner disproval of the content.

[HugoGresse]

Searching for CSG, Three.js only return this one, the others seems not documented. I'm happy with this one though!

[gkjohnson]

Hi Hugo! Thanks for the suggestion - I think you're right that the "simple" CSG example is a bit more complicated code-wise. The "multi-material" CSG example is a bit more simple but I agree that a basic, single-operation example would be good for newcomers.

It could be great to have a more static example, like substracting a circle from a rectangle sort of thing...

Let me know what you think, I can also do a quick PR for that.

This would be great. And maybe you can rename "Simple CSG" to "Interactive CSG" in the README so it's more clear, as well.