Future SmartMatrix Library 4.x Todos

[embedded-creations]

These are things that didn't make it into SmartMatrix Library 4.0

• APA102 GBC calculation efficiency, use bitwise OR instead of max()?
• Teensy 4 APA102 - optimize APA buffer cache flush
  • Move cache flush out of FLEXIOSPI.Transfer() and into "low priority isr (apaRowCalculationISR) instead of the high priority isr (apaRowShiftCompleteISR), and only the newly changed part of the cache needs to be flushed after each calculation." (Eric)
• MultiRowRefreshMapping general improvements
  • Do more testing with MultiRowRefreshMapping to make sure it's working
  • Make it easier to determine mapping and add a new map