JMRI Model Railroad Interface

This file is a development of the existing 'Hornby8215.xml'. It does two
things:

(1) Drastically prunes what the decoder file claims the decoder can do, to
reflect the documentation supplied, and experimental results with a
recently purchased R8215.

(2) Renames the family to reflect Hornby's branding, and the existence of
multiple decoders from them in this family. As such, it could co-exist with
'Hornby8215.xml', but I believe it should supersede it.

It has been tested by two users on differing versions of JMRI (2.0 and
2.1.4).

It is my first decoder definition file, and it may contain newbie errors
that lie latent in my testing!