Sqlmath

- add addon functions dbOpen(), dbClose(), dbExec(). but ci works only in linux.

- add extension-function b64decode()
- add c-function sqlite3_exec_get_tables().
- add target_cli.
- binaries - upload darwin/linux/win32 binaries to gh-pages.
- begin compiling sqlmath.c.
- jslint file sqlmath.js.
- merge file test-old-prepare.db into test-old.js.

- add coverage testing.
- add extension-function support.
- fork repo as sqlmath.

- build: rebuild binaries before publishing [1426](https://github.com/mapbox/node-sqlite3/pull/1426)

- dep: node-addon-api to ^3.0.0 [1367](https://github.com/mapbox/node-sqlite3/pull/1367)
- bug: bad comparison of c string [1347](https://github.com/mapbox/node-sqlite3/pull/1347)
- build: Install files to be deployed [1352](https://github.com/mapbox/node-sqlite3/pull/1352)
- sqlite3: upgrade to 3.32.3 [1351](https://github.com/mapbox/node-sqlite3/pull/1351)
- bug: worker threads crash [1367](https://github.com/mapbox/node-sqlite3/pull/1367)
- bug: segfaults [1368](https://github.com/mapbox/node-sqlite3/pull/1368)
- typo: broken link to MapBox site [1369](https://github.com/mapbox/node-sqlite3/pull/1369)

- prebuilt: Node 14 support, dropped support for all version of Node < 10 [1304](https://github.com/mapbox/node-sqlite3/pull/1304)
- prebuilt: add electron 7.2 [1324](https://github.com/mapbox/node-sqlite3/pull/1324)
- napi: refactor codebase to use N-API instead of NAN (+ various improvements) [1304](https://github.com/mapbox/node-sqlite3/pull/1304)
- trace: don't require throw to add trace info for verbose [1317](https://github.com/mapbox/node-sqlite3/pull/1317)
- ci: remove permission setting [1319](https://github.com/mapbox/node-sqlite3/pull/1319)