Sample rate slightly off

[Stefan Drissen]

Pointed out and fixed by @AntonyDTA (Thanks!).

As discovered earlier, the SAM Coupé renders 50.08 frames per second, not 50. The Amiga -> SAM pitch conversion tables were never adjusted.

Starting at note D#2 the difference starts at 1/256, increasing to 2/256 for note A#3:

note frequencies.ods