Noise level mod and more updates

Now noise level can be adjusted as a simple patch parameter which also stored and restored.  Just like on a Juno! Also added a new memory dump function that lets import and export of the whole patch memory. For more convenience the MIDI Thru can be switched off to ease recording multiple takes.  Manual is updated according to these changes.

mmmmm

New chips at my hand. The new Io series will be equipped with fresh Atmel ATTiny4313 micro-controllers.