feat(build): add general copy/multicopy method

tools/build/util.js

@@ -8,17 +8,37 @@ module.exports = {
   streamToPromise: streamToPromise,
   insertSrcFolder: insertSrcFolder,
   filterByFile: filterByFile,
-  forEachSubDir: forEachSubDir
+  subDirs: subDirs,
+  forEachSubDir: forEachSubDir,
+  forEachSubDirSequential: forEachSubDirSequential
 };
 
+function subDirs(dir) {
+  return [].slice.call(glob.sync('*/', {cwd: dir}));
+}
 
 function forEachSubDir(dir, callback) {
-  var moduleFolders = [].slice.call(glob.sync(dir + '/*'));
-  return Q.all(moduleFolders.map(function(subDir) {
-    return callback(subDir);
+  var dirs = subDirs(dir);
+  return Q.all(dirs.map(function(subdir) {
+    return callback(path.join(dir, subdir));
   }));
 };
 
+function forEachSubDirSequential(dir, callback) {
+  var dirs = subDirs(dir);
+  return next(0);
+
+  function next(index) {
+    if (index < dirs.length) {
+      return callback(path.join(dir, dirs[index])).then(function() {
+        return next(index+1);
+      });
+    } else {
+      return true;
+    }
+  }
+}
+
 function processToPromise(process) {
   var defer = Q.defer();
   process.on('close', function(code) {