added es6 distribution & gulp task for es6 distribution

package.json

@@ -1,6 +1,6 @@
 {
   "name": "yjs",
-  "version": "0.6.41",
+  "version": "0.6.42",
   "description": "A framework for real-time p2p shared editing on arbitrary complex data types",
   "main": "y.js",
   "scripts": {
@@ -46,6 +46,7 @@
     "babel-preset-es2015": "^6.1.18",
     "babelify": "^7.2.0",
     "browserify": "^12.0.1",
+    "eslint": "^1.10.2",
     "gulp": "^3.9.0",
     "gulp-bump": "^1.0.0",
     "gulp-concat": "^2.6.0",
@@ -61,11 +62,12 @@
     "gulp-shell": "^0.5.1",
     "gulp-sourcemaps": "^1.5.2",
     "gulp-tag-version": "^1.3.0",
-    "gulp-uglify": "^1.4.2",
+    "gulp-uglify": "^1.5.1",
     "gulp-util": "^3.0.6",
     "gulp-watch": "^4.3.5",
     "minimist": "^1.2.0",
     "pre-commit": "^1.1.1",
+    "regenerator": "^0.8.42",
     "run-sequence": "^1.1.4",
     "standard": "^5.2.2",
     "vinyl-buffer": "^1.0.0",