Updated renderer to allow viewport to be set manually

[ZeppelinGames]

• Updated setViewport function on Renderer
• Added updateViewport function on Renderer
• Reordered state and setSize initialisation in Renderer

Allows for functionality using normalized coordinates:

// w, h, x=0, y=0
renderer.setViewport(0.5, 0.5, 0, 0);
renderer.render({ scene, camera });

By default/on screen resize viewport resets to [1,1,0,0] (setViewport(1,1))

[ZeppelinGames]

Will allow for rendering the same camera twice using the same renderer context
(ignore the jank)

// Render camera at bottom left corner
camera.position.z = 5;
renderer.setViewport(0.5, 0.5, 0, 0);
renderer.gl.enable(renderer.gl.SCISSOR_TEST);
renderer.setScissor(viewport3D.clientWidth * 0.5, viewport3D.clientHeight * 0.5);
renderer.render({ scene, camera });
renderer.gl.disable(renderer.gl.SCISSOR_TEST);

// Render same camera at bottom right corner
camera.position.z = 3
renderer.setViewport(0.5, 0.5, 0.5, 0);
renderer.gl.enable(renderer.gl.SCISSOR_TEST);
renderer.setScissor(viewport3D.clientWidth * 0.5, viewport3D.clientHeight * 0.5, viewport3d.clientHeight * 0.5);
renderer.render({ scene, camera });
renderer.gl.disable(renderer.gl.SCISSOR_TEST);