Follow cl-gmath acb158a: the requirements, the tests and CI name SBCL
alone, and the pages no longer say what CCL's accessors check, that CCL
boxes doubles, or that CCL computes the same bits.
Doubles, the choice of SIMD kernels when an image starts and the NEON
kernels, which the wiki did not describe yet, and f68ff1e's 2D
transforms, functions of single numbers, and the vectors' constructors
and accessors. New pages: 2D Transforms, Single Numbers and Doubles.
Getting started, the conventions, vectors, matrices, quaternions,
transforms and cameras, results without allocation, batches and SIMD,
errors, and the API reference.
