Use geodetic calculations from Proj 4.9

[pramsey]

As of proj4.9, geodetic distance and area on spheroid will be available from proj4

​http://gis.stackexchange.com/questions/84012/how-can-i-obtain-the-same-area-values-provided-by-the-census-for-tiger-boundarie

The area in particular does not have failure cases around the poles or over the equator, so would be an improvement on the current code. Could also copy the code directly into liblwgeom for support on earlier versions of proj.

[pramsey]

A much more complete patch for this is sitting waiting to be reviewed and integrated.