chore: webpack upgrade (#98)

* upgraded to webpack 4.x

* updated webpack

examples/app.js

@@ -0,0 +1,18 @@
+require('codemirror/lib/codemirror.css');
+require('../src/mergely.css');
+
+$(document).ready(function () {
+	$('#mergely').mergely({
+		license: 'lgpl',
+		cmsettings: {
+			readOnly: false
+		},
+		_debug: '',
+		lhs: function(setValue) {
+			setValue('the quick red fox\njumped over the hairy dog');
+		},
+		rhs: function(setValue) {
+			setValue('the quick brown fox\njumped over the lazy dog');
+		}
+	});
+});