Experimental WASI/WASM build

Download wasi-sdk https://github.com/WebAssembly/wasi-sdk

Compile tinygltf without C++ exceptions and threads. See Makefile for details (NOTE: TinyGLTF itself does not use RTTI and threading feature(C++ threads, posix, win32 thread))

Build loader_example.cc

$ /path/to/wasi-sdk-16.0/bin/clang++ ../loader_example.cc -fno-rtti -fno-exceptions -g -Os -I../ -o loader_example.wasi

Tested with wasmtime. https://github.com/bytecodealliance/wasmtime

Set a folder containing .gltf file to --dir

$ wasmtime --dir=../models loader_example.wasi ../models/Cube/Cube.gltf

T.B.W. ...

EoL.