Calculator graphics drawing benchmark

[robve]

DavidM: thank you for sharing the details how the approach worked with GROBs. Note that it is permitted to draw the entire image to a GROB first and display the GROB at the end. That will still count for this benchmark, because it optimizes the drawing speed of the entire image to a buffer, not bypass line drawing. I've used UseBuffer and PaintBuffer with the Ti-nspire to do just that.

C.Ret: great to see the HP-28S and the HP-41C additions to the benchmark list. Using the printer with the HP-41C offers a creative contribution!

- Rob