WORK IN PROGRESS: s2 geometry functions - needed for the new regional scoreboards
undefimned fefault to true, rather than false, when adding a layer - more likely whats wanted
more s2geometry code
we have enough now to calculate the cell containing a lat/lng, and to calculate the lat/lng for a cell center/boundary
not certain the hibbert curve stuff is right yet...
WORK IN PROGRESS plugin to draw the scoring regions on the map
for #741