To make life easier later, we might want to normalize all scene aspect ratio to the same value (besides square and upside-down). A few things we should change for this are:
[x] enable setting resolution of renders either as height or width
[x] prefer width for setting rendering size
[x] when setting y FOV, keep the film height fixed, not the width
or at least consider the options here
[x] wrote down some common formats from movies and photography in the documentation
[x] adopt a common format, probably from video/movies
To make life easier later, we might want to normalize all scene aspect ratio to the same value (besides square and upside-down). A few things we should change for this are: