Resolve spatial reference extents issue

[rghosh0]

Resolve spatial reference extents issue. Currently proper tile layout depends on knowing the precise extents of the tile pyramid's spatial reference. Either remove this dependency or create a dependable database of projection extents.

The extents from the following websites are unreliable:

epsg-registry.org
epsg.io
spatialreference.org

The geopackage files themselves do not include the projection extents.

I have not yet found a way to use any software (e.g. Proj.4, GDAL/OGR) to acquire the extents.

Currently we choose extents using the epsg.io extents as a starting point, and alter them to be in harmony with the desired tile pyramid and layer extents. We should not have to do this, and it may not be robust.

See also:
http://gis.stackexchange.com/questions/202771/how-to-get-the-extents-of-a-spatial-reference-system