Update and test build, esp in NodeJS

[thadk]

Short version:
I used the below line to replace https://github.com/codeforboston/anypia-js/blob/master/anypiajs/CMakeLists.txt#L67 along with ./installbuild-emscripten-mac.sh to compile AnyPIAJS.mjs for the Windfall Awareness project using the July 2020 (>= 1.39.17) version of Emscripten (I used a new emscripten promise feature in the line below).

set_target_properties(${PROJECT_NAME} PROPERTIES COMPILE_FLAGS "-s USE_BOOST_HEADERS=1" LINK_FLAGS "-s USE_BOOST_HEADERS=1 -s EXPORT_ES6=1 -s USE_ES6_IMPORT_META=1 -s ENVIRONMENT=web -MODULARIZE=1 -s WASM=1 --bind ${EXPORTED_FUNCTIONS} ${EXPORTED_RUNTIME_METHODS}")

But this change is not committed to this repository yet. Also ENVIRONMENT=web does not work with NodeJS so cannot be used in automated testing such as what we might want to do with TravisCI in this repo.

More details at codeforboston/windfall-elimination#209