Refactor(ES6): Lint fixes

lib/OptionsApply.js

@@ -5,6 +5,6 @@
 "use strict";
 
 class OptionsApply {
-	process(options, compiler) { }
+	process(options, compiler) {}
 }
 module.exports = OptionsApply;

lib/ProgressPlugin.js

@@ -25,7 +25,7 @@ class ProgressPlugin {
 			compiler.compilers.forEach(function(compiler, idx) {
 				compiler.apply(new ProgressPlugin((p, msg) => {
 					states[idx] = Array.prototype.slice.apply(arguments);
-					handler(...[
+					handler.apply(null, [
 						states.map(state => state && state[0] || 0).reduce((a, b) => a + b) / states.length,
 						`[${idx}] ${msg}`
 					].concat(Array.prototype.slice.call(arguments, 2)));