If desired, stitch poles before projecting.

When a projection is specified, the topology is constructed in Cartesian
coordinates after the projection is applied, so pole stitching is implicitly
disabled. Instead, we must stitch poles before the projection is applied. This
fixes the remaining issue in mbostock/d3#1802.
Add --version; fixes #133.
Merge branches 'stitch-poles-when-projecting' and 'version' into 1.5.2
Merge branch '1.5.2'