[WP 34S] Enhanced Y register display: fractions, bugfixes etc.

[Paul Dale]

Everything in the volatile memory disappears between keystrokes. Nothing there should ever be considered initialised.

There are a small number of state variables that are preserved between keystrokes (by stealing the LCD buffer memory) and you might be able to reuse some of these for some purposes -- you won't be able to grab any of the permanently however.

- Pauli