Development helpers and tests for libnethack.a and nethack.js.

Copy these files to the NetHack root directory. Commands include:
* run.sh wasm - rebuild makefiles and build nethack.js
* run.sh runwasm - simple testing of nethack.js
* run.sh lib - rebuild makefiles and build libnethack.a
* run.sh runlib - simple testing of libnethack.a
* run.sh bin - build the MacOS binary