Render errors when crossing the 180th meridian

[hholzgra]

With a bounding box crossing the antimeridian only the part left of it is rendered correctly, the part beyond 180° is just filled with the background colour.

To render things correctly we'd probably have to split the rendering area in two parts vertically along the 180° line and render things up to 180°, and starting at -180°, separately.

[hholzgra]

[hholzgra]

See also eg:

https://github.com/mapnik/mapnik/issues/847