Tippecanoe

* Added --calculate-feature-index option
* Added "count" accumulation type to --accumulate-attribute
* Work in progress on binning of point features in overzoom. Not ready for use yet.

* Fix bad interaction between --retain-points-multiplier and stopping early when the tile feature limit is reached
* Fix another bad interaction between --retain-points-multiplier, dropping-as-needed, and variable depth tile pyramids
* Add optional BUILD_INFO string to version
* Reorder overzoom logic to clip before dealing with multiplier and filters
* When --generate-variable-depth-tile-pyramid is in use, report the actual highest zoom generated as tileset maxzoom

* Correct `antimeridian_adjusted_bounds` latitude calculation when vertices extend beyond the edge of the Mercator plane

* Add --generate-variable-depth-tile-pyramid option
* Add --line-simplification and --tiny-polygon-size options to tippecanoe-overzoom
* Adjust tile feature limit for --retain-points-multiplier
* Tune convergence rate for --coalesce-densest and --drop-densest
* Fix overreported drop and coalesce counts in strategies

* Add multi-tile input to tippecanoe-overzoom

* Rework --coalesce-densest-as-needed and --drop-densest-as-needed to look better
* Add --maximum-string-attribute-length option