L3bin scheme as mesh

[mdsumner]

finally do this right

## sosoc/croc
init <- initbin(36)
 x <- bin2bounds(1:init$totbins, 36)
 X <- c(t(cbind(x$west, x$east, x$east, x$west)))
 Y <- c(t(cbind(x$south, x$south, x$north, x$north)))
 XYZ <-vorsph::ll2cart(cbind(X, Y, 0))
 quads3d(XYZ, col = rep(sample(grey.colors(25)), each  = 4))

• proper mesh with unique coords
• ability to segmentize (loxodromes), as shared boundaries
• explore with s2