Tippecanoe

* Fix some undefined behavior bugs, one of which results in slight changes to line simplification choices

* Stabilize feature order in tippecanoe-overzoom when --preserve-feature-order is specified but the sequence attribute is not present

* Polygon dust returns to having the attributes of the contributing feature nearest the placeholder instead of the contributing feature with the largest area.

* Adjust tile size limit with --retain-points-multiplier dynamically within each tile, to allow multiplier features at high zooms if other features are being dropped as-needed

* Add --unidecode-data option to allow case-insensitive filter comparisons of transliterated strings

* Change -fraction-as-needed feature dropping to be consistent across tiles and zoom levels, and to follow the same pattern as point dropping by zoom level
* With -as-needed feature dropping, drop or retain entire multiplier clusters instead of individual features
* Sort the features within each multiplier cluster by its retention priority, for more consistency between zoom levels in filtered feature choice