[build] added gulp builder

gulpfile.js

@@ -0,0 +1,31 @@
+"use strict";
+const os = require('os');
+const gulp = require('gulp');
+const clean = require('gulp-clean');
+const Sdk = require('./tasks/sdk');
+const Config = require('./config.json');
+const prepare = require('./build/prepare');
+
+if (Config.SdkDir) {
+    Sdk.dir = Config.SdkDir;
+}
+
+exports.clean = () => {
+    return gulp.src('target/*', {read: false}).pipe(clean());
+};
+
+const merge = (value) => {
+   if (typeof value === 'string') {
+       value = require(value);
+   }
+   for (let key in value) if (value.hasOwnProperty(key)) {
+       exports[key] = value[key];
+   }
+};
+
+exports.update = prepare.update;
+merge('./build/prepare');
+merge('./build/client');
+merge('./build/server');
+
+exports.default = gulp.series(exports.clean, exports.client, exports.server);