basic region map; non-interactive for now and working with dummy data instead of real cell/region records
build region map from records (only initial build; updates not implemented yet)
dealing with invalid regions and cells without regions
some cleanup; added handling of deleted cells (now displayed instead of ignored)
added missing case folding
updating region map on changes to region and cell records
added region map tooltips
inverted region map y-axis
Merge branch 'region'