references acidanthera/bugtracker#1280

 - Revert to simpler CustomDelays bool setting (avoid user errors)
 - Update docs to clarify correct use of key repeat settings on KeySupport AMI vs KeySupport V1/V2 vs non-KeySupport
 - Update PointerSpeedMul failsafe to OEM 1
 - Update key delay failsafes to OEM 50, 5

Fixes an issue where drivers requesting AppleEvent events early (e.g. CrScreenshotLib) cause caching of a screen resolution that is later changed, leading to an out-of-sync cursor movement rectangle.

This MSR is actually documented today and is apparently read
incorrectly by lots of software. They inspect the current multiplier,
not the max one. This mistake resulted in hardware starting with
reduced multiplier (e.g. 6.5 instead of 8.5 in MacBook5,2) to report
wrong frequency.

Some other systems are still broken.