Update README examples to use wasm32-unknown-unknown

Author: germania

README.md

@@ -2,7 +2,7 @@
 
 [![npm](https://img.shields.io/npm/v/rust-wasm-loader.svg)](https://www.npmjs.com/package/rust-wasm-loader)
 
-### Usage
+## Usage
 
 This is a simple Webpack loader that shells out to cargo to build a Rust project targeting WebAssembly. See [this post](https://users.rust-lang.org/t/compiling-to-the-web-with-rust-and-emscripten/7627) for
 more details on using Rust to target the web.
@@ -38,28 +38,25 @@ module.exports = {
 
 Note: if you are using `file-loader`, make sure to add `.wasm` to the test field, otherwise the module will not be copied! (e.g. `test: /\.(wasm|jpg|jpeg|png|gif|svg|eot|ttf|woff|woff2)$/i,`).
 
-Make sure you have the `cargo`, `rustc`, and `emsdk` binaries somewhere in your `PATH`.
+Make sure you have the `cargo`, `rustc`, and (optionally) `emsdk` binaries somewhere in your `PATH`.
 Require and initialize the wasm module:
 
 ```js
 const wasm = require('./main.rs')
-wasm.initialize().then(module => {
+wasm.then(module => {
   // Use your module here
-  const doub = module.cwrap('doub', 'number', ['number'])
-  console.log(doub(21))
+  console.log(module.doub(21))
 })
 ```
 
 or with async/await:
 
 ```js
-async function loadAndUseWasm() {
-  const wasm = require('./main.rs')
-  const module = await wasm.initialize()
-  const doub = module.cwrap('doub', 'number', ['number'])
-  console.log(doub(21))
+async function loadwasm() {
+  const lib = await require('./lib.rs');
+  // Use your module here
+  console.log(lib.doub(21));
 }
-loadAndUseWasm()
 ```
 
 ### Configuration
@@ -70,6 +67,7 @@ The following options can be added to the Webpack loader query:
 | ---- | ----------- | -------- | ------- |
 | `release` | Whether or not to pass the `--release` flag to cargo | false | false |
 | `path` | Path to your webpack output folder relative to project root | true | '' |
+| `target` | Allows one to specify `wasm32-unknown-emscripten` as build target | false | 'wasm32-unknown-unknown' |
 
 ### Example