Implemented Perlin Noise.

A test render, and user interface screenshot for that test render.
As you can see user interface is pretty basic. However it has undo and redo and parameter descriptions; also, there's whole "plugin compiler" thing behind the scenes, binding editable parameters to the internals, and binding the internal connections. In this example, the result of perlin noise is bound to v_density parameter of "Clouds" (so that the density of cloud is set by perlin noise), and perlin noise's Evaluation Pos. is bound to cloud's EvaluationPosition channel (so that the perlin noise is evaluated at position where "Clouds" ask it to be evaluated). "Clouds" themself are bound to Volumetrics, the core renderer.

For now, user interface doesn't have working "render" buttons or the like; scene file is saved and then rendered with CLI version. It gonna take lot of time until user interface becomes actually usable by normal users.