Release 43.0 for the A500-SD-Plus controller

This is the first release of the SD SPI driver based on the excellent lide.device for my A500-SD-Plus controller
The driver in this release must either be loaded using loadmodule or "burned" to a custom Kickstart ROM.

"SD_test" is a small test program that can be run from the CLI. It benchmarks some critical functions in the SD driver code and performs continuous SD card reads.

Full Changelog: Release-42.0...Release-43.0