update README.md to be more JS-engine agnostic
update README.md to be more JS-engine agnostic

citisolo/wabt,WebAssembly/wabt,WebAssembly/sexpr-wasm-prototype,WebAssembly/sexpr-wasm-prototype,citisolo/wabt,citisolo/wabt,WebAssembly/wabt,WebAssembly/sexpr-wasm-prototype,WebAssembly/sexpr-wasm-prototype,WebAssembly/sexpr-wasm-prototype,citisolo/wabt,WebAssembly/sexpr-wasm-prototype,WebAssembly/wabt,citisolo/wabt,WebAssembly/wabt,citisolo/wabt,WebAssembly/wabt