Support for this Lua module has been discontinued.

Equivalent functionality is available from the dht module in the NodeMCU
firmware code base. Refer to `docs/en/modules/tsl2561.md` for API
documentation.

The original Lua code can be found in the [git repository](https://github.com/nodemcu/nodemcu-firmware/tree/2fbd5ed509964a16057b22e00aa8469d6a522d73/lua_modules/tsl2561).