Add GeoJSON output support.
Add GeoJSON output format to enumerate as well.
First attempt at point clouds
Better random seed for point clouds
Don't drop points in the point cloud loop.

Clusters are already being dropped in the outer loop, so dropping
more in the inner loop makes for wrongly dim lower zooms.
Make point clouds be circular instead of square
Accept feet or meters as units for point cloud radius
Use the actual radius specified for the point clouds
Hold off skipping dots until clouds are much smaller than a pixel.
Fix random seed. Point clouds are consistent between zooms now.
Skip the loop and just draw a pixel when the cloud radius is subpixel.
Handle point clouds big enough to cross more than one tile boundary
Fix backwards metric conversion.
Center clouds instead of hanging them down and to the right.
Skip the loop if none of the cloud can overlap the tile.
Oops, non-clouds need to look above for overlap, not below
Merge branch 'geojson'

Conflicts:
	enumerate.c
	render.c
Support 64-bit output for new dump formats
Merge branch 'pointcloud'