Fix camera code and associated text to account for new aspect ratio calculations #527
Description
After moving the initial image generation from a resolution of 200×100 to a larger resolution, we forgot to update the associated text.
In addition, in the move to a computed image resolution height based on aspect ratio, the associated viewport does not receive the same treatment, but instead uses a horizontal vector 4 units in length, and a vertical vector 2 units in length (matching the original 200:100 aspect ratio). We need to update the viewport computation throughout the books, and in source code.