Update to ES modules

Author: MikuroXina

README.md

@@ -5,24 +5,20 @@ The Lua runtime for Node.js.
 ## Usage
 
 ```js
-const { doFile, doString } = require('do-lua');
+import { doFile, doString } from 'do-lua';
 
 const program = `
 print("Hello, World!")
 `;
 
-doString(program).then(() => {
-  console.log("Done doString");
-})
-doFile('examples/test1.lua').then(() => {
-  console.log("Done doFile");
-})
+await doString(program);
+await doFile('examples/test1.lua');
 ```
 
 You cannot use `this` in functions of the passing table on `loadProgram`. Use arrow function instead of that.
 
 ```js
-const { loadProgram } = require('do-lua');
+import { loadProgram } from 'do-lua';
 
 const state = loadProgram(`
 obj.ox = 50;
@@ -37,8 +33,8 @@ const table = {
 };
 state.setTable('obj', table);
 
-state.run().then((G) => { // G is global table exclusive "package" and "_G"
-  console.log("ox: ", G.obj.ox); // 50
-  console.log("Message: ", message); // Hello, World!
-});
+// G is global table exclusive "package" and "_G"
+const G = await state.run()
+console.log("ox: ", G.obj.ox); // 50
+console.log("Message: ", message); // Hello, World!
 ```

index.js

@@ -1,18 +1,20 @@
-const native = require('./native');
+import * as native from './native';
 
-function StateConstructor(program) {
-    this.program = native.loadProgram(program);
-};
+class StateConstructor {
+    constructor(program) {
+        this.program = native.loadProgram(program);
+    }
 
-StateConstructor.prototype.setTable = function setTable(name, table) {
-    native.setTable(this.program, name, table);
-};
+    setTable(name, table) {
+        native.setTable(this.program, name, table);
+    }
 
-StateConstructor.prototype.run = function run() {
-    return new Promise((resolve) => native.run(this.program, resolve));
-};
+    run() {
+        return new Promise((resolve) => native.run(this.program, resolve));
+    }
+}
 
-module.exports = {
+exports = {
     doStringSync: native.doStringSync,
     doString: native.doStringAsync,
     doFileSync: native.doFileSync,

index.test.js

@@ -1,4 +1,4 @@
-const { doFile, doString, loadProgram } = require('.');
+import { doFile, doString, loadProgram } from '.';
 
 test('doString', () => {
   const program = `