Support HD(1600Kb) floppy disk images.

[xolod79]

Please, Add support Support HD(1600Kb) floppy disk images.
On this site http://acorn.revivalteam.de/?site=Downloads
have some Demos .( example http://acorn.revivalteam.de/Download/Images/Demos09.zip )

I found some information:
http://www.marutan.net/rpcemu/cgi/download.php?sFName=0.9.1/rpcemu-0.9.1.tar.gz
In src/fdc.c
and
https://sourceforge.net/p/hxcfloppyemu/code/HEAD/tree/HxCFloppyEmulator/libhxcfe/trunk/sources/loaders/acornadf_loader/acornadf_loader.c#l110
90 line.
and
https://github.com/simoninns/OpenAcornExplorer/tree/master/OpenAcornExplorer