plane packing - use nPackedPlanes in address calculation
WIDTH = BYTES_PER_ROW*nPanels, fix getPixel (which had not been adapted for multiple panels)
more using WIDTH for BYTES_PER_ROW * nPanels
Move setRefresh code
Add dimmer setDim(delay)
Error checking - validate pins
Fix Color888 - shifts were wrong, add annotations to dump
ASSERT - temporary version