camera worldToScreen not documented

The very useful function camera.worldToScreen(position) does not seem to be in the documentation. I noted that the functionality was missing which bothered me on grounds of api symmetry. Later I saw an example where it was used. I think it should be added to the doc.

@DavidLeibs sorry about that! There’s an update currently in review with Apple, but we’ll add it to the one after that.