Calculating sunrise and sunset - v2

Over the last couple of weekends I've moved the code I converted to work on the RC2014 onto the MZ-700. Apart from some general tidying up, I've made a few changes to the input and output subroutines.

The input subroutine still doesn't check that the values entered are sensible (30th February 2022 is accepted without a blink), but at least it now expects the timezone to be stated as a positive number when you are East of GMT (rather than West).

I've improved the output, and also added some rudimentary graphics to show the Sun's track between sunrise and sunset using pseudo pixels. I'm calling it finished for now.

I really ought to go back to coding the brickbreaker game I started but never completed last Autumn ...

Code for the sunrise / sunset calculator (github).