Document the recently added methods.
Updates #11.

Signed-off-by: Shawn Laffan <shawnlaffan@gmail.com>
Make the internal parse methods private methods.

Signed-off-by: Shawn Laffan <shawnlaffan@gmail.com>
Make the extract methods internal.

Signed-off-by: Shawn Laffan <shawnlaffan@gmail.com>
Make more methods internal (get_bytes and the read header methods).

Signed-off-by: Shawn Laffan <shawnlaffan@gmail.com>
Further privatisation.  Getting headers and the read methods.

Signed-off-by: Shawn Laffan <shawnlaffan@gmail.com>
More privatisation.  All the inner maths subs, plus var.

Signed-off-by: Shawn Laffan <shawnlaffan@gmail.com>