Infinite loop fixes, minimizing changes to behavior (#345)

* Divide-and-conquer polygon cleaning

* Catch the case where the gap can't be increased further

* Catch the case where we try to keep impossibly many features

* Make label points earlier in the tiling process

* Another case where it could try to drop even after already limiting.

* And do not coalesce on impossibly small geometries

* Add missing return

* Update version and changelog

tests/ne_110m_admin_0_countries/out/-z2_--convert-polygons-to-label-points.json

@@ -9,7 +9,6 @@
 "maxzoom": "2",
 "minzoom": "0",
 "name": "tests/ne_110m_admin_0_countries/out/-z2_--convert-polygons-to-label-points.json.check.mbtiles",
-"strategies": "[{},{},{\"tiny_polygons\":1}]",
 "type": "overlay",
 "version": "2"
 }, "features": [