H3

Added
- Functions for `cellToChildPos` and `childPosToCell` (719)

Fixed
- Fixed possible signed integer overflow in `h3NeighborRotations` (707)
- Fixed possible signed integer overflow in `localIjToCell` (706, 735)

Changed
- `assert` on defensive code blocks that are not already covered. (720)
- `clang-format` upgraded to version 11. (734)

Fixed
- Changing an internal `float` to `double` improves the precision of geographic coordinate output (652)
- Fixed compacting all children of a resolution 0 cell (679)
- Fixed possible signed integer overflow in `maxGridDiskSize` (686)
- Fixed possible use of uninitialized values in `cellToVertex` (683, 690)
- Fixed possible out of bounds read in `localIjToCell` (684)
- Fixed possible memory leak in `compactCells` (685)
- Fixed possible out of bounds read in `areNeighborCells` (677)
- Fixed possible memory leak in `cellsToLinkedMultiPolygon` (673)

Changed
- Build script does not use toolchain file (641)
- Removed a duplicated include preprocessor directive (682)
- Improvements to the fuzzer suite and their automatic runs in CI (671, 674, 687)
- Increased test coverage (642)
- Added a fuzzer targetting internal `algos.c` functions (675)

Breaking changes
- Rename functions according to the terminology RFC (622, 586, 571, 403, 466, 495, 466)
- Functions that can experience errors now have an `H3Error` return value. (617, 586, 581, 551, 550, 509, 505, 507, 508, 503, 478, 468, 436, 359)
- Cell count parameters use `int64_t` instead of `int`.
- `polygonToCells` (previously `polyfill`) accepts a flags argument for future expansion. (570)
- `cellToLocalIj` and `localIjToCell` accept a mode argument for future expansion. (586)
- `exactEdgeLength` functions renamed to `edgeLength` (639)

Fixed
- Fix polyfill bug when vertex latitude exactly matches cell center. (603)
- A number of issues detected via unit tests and fuzzers were fixed. (568, 562, 558, 559, 560, 430)
- `polygonToCells` returns an error if Infinity is passed in. (636)

Changed
- The file `CMakeTests.cmake` is no longer included if `ENABLE_TESTING` is off. (609)

Added
- Vertex mode and associated functions: (422, 420, 417)
- `cellToVertex(cell, vertexNum)`
- `cellToVertexes(cell, out)`
- `vertexToLatLng(vertex, out)`
- `isValidVertex(vertex)`
- `h3` CLI application. (556, 497)

Other changes
- Generally use `lng` instead of `lon`
- Closed-form implementation of `numHexagons`
- A number of fuzzer harnesses are now included in the H3 core library. (557, 553, 545, 433)
- Additional benchmarks are added and benchmarks are regularly run in CI. (524, 518)

Breaking changes
- `exactEdgeLength` functions renamed to `edgeLength` (639)

Fixed
- `polygonToCells` returns an error if Infinity is passed in. (636)

Breaking changes
- `distance*` functions (`distanceKm`, etc) renamed to `greatCircleDistance*`. (622)
- Error code `E_MEMORY` renamed to `E_MEMORY_ALLOC`. (617)

Fixed
- Fix polyfill bug when vertex latitude exactly matches cell center. (603)

Changed
- The file `CMakeTests.cmake` is no longer included if `ENABLE_TESTING` is off. (609)