Repeat items at edges in history.

[trypsynth]

Currently, if there's only one item in the history, pressing up and down won't say anything. Make it:

• Repeat items at edges
• Assign one of the buttons around the d-pad to say the current history item.

[trypsynth]

One other thing I think we should do is make the items repeat at the edge when moving left or right. We should also assign these to beeps on the buzzer. The edge sounds that is, not just scrolling.