Enable tone/effects library for rp355.

Implement the recent addition of the tone/effects library for the rp355.

Get rid of USB_POSITION.

Add tone lib A for rp355.

Minor comment changes.

Remove a couple of commented out lines.

gdigi_xml.h

@@ -36,6 +36,5 @@ typedef struct {
 XmlSettings *get_xml_settings(guint id, guint position);
 gboolean value_is_extra(EffectValues *val, int value);
 gchar * map_xml_value(XmlSettings *xml, EffectValues *values, gint value);
-// gchar *get_xml_label(guint id, guint position, gint type);
 
 #endif /* GDIGI_XML_H */