Implementation of the version 5 of the Squirrel noise function as introduced by Squirrel Eiserloh at GDC.
Generated noise is checked against the reference implementation and should be bit-for-bit equivalent, with the exception that returned floating point numbers are double precision since OCaml only support these.
This is a pure OCaml implementation and not stubs to the reference C implementation so as to be platform agnostic - eg. targeting js_of_ocaml.