Scala Native on WebAssembly Demo

First, locally publish https://github.com/scala-native/scala-native/pull/1363 with sbt rebuild_x32.

Then, run the Scala Native linker with sbt nativeLink, this will produce errors during compilation and linking, but this is okay because we only care about the generated LLVM.

Finally, run Emscripten to compile to WebAssembly:

emcc target/scala-2.11/native/lib/*.c target/scala-2.11/native/lib/gc/none/**.c target/scala-2.11/native/lib/*.cpp target/scala-2.11/native/*.ll -s WASM=1 -s ALLOW_MEMORY_GROWTH=1 -s ERROR_ON_UNDEFINED_SYMBOLS=0 -o index.html

Then open up index.html in a web browser (you may need to serve the directory as a local server due to security restrictions).