mvg multi view geometry

Run tests with:

cargo test

TODO

• Make intrinsic parameters a trait so that different models can exist.
• Make 2D and 3D coordinate types unified and use PhantomData on an enum to distinguish world and camera (3D) or distorted and undistorted (2D)
• Vectorize all operations (allows e.g. fearless_simd to be used)
• Pixel -> 3D transformations should return ncollide rays (rather than points)
• Make extrinsic a trait so +z forward and -z forward cameras can co-exist
• Use mint for external api (rather than nalgebra)?
• Remove all "water" handling into separate crate. Especially important since I switched the signature of project_3d_to_pixel() to return T instead of Result<T>, which requires potentially panic!ing now (in expect()). See tag "laksdfjasl".