added babel compiler to tests

Author: Alexey Litvinov

.babelrc

@@ -0,0 +1,5 @@
+{
+  "presets": [
+    "es2015"
+  ]
+}

package.json

@@ -9,6 +9,7 @@
   "scripts": {
     "test": "NODE_PATH=$(pwd)/test/tokens/node_modules $npm_package_scripts_test_unit --harmony_destructuring --harmony_spread_arrays --use_strict",
     "test:w": "NODE_PATH=$(pwd)/test/tokens/node_modules $npm_package_scripts_test_unit --watch --harmony_destructuring --harmony_spread_arrays --use_strict",
+    "test:babel": "NODE_PATH=$(pwd)/test/tokens/node_modules $npm_package_scripts_test_unit --compilers js:babel-register",
     "test:unit": "mocha --require test/setup.js --ui tdd test/*/*.js"
   },
   "repository": {
@@ -45,6 +46,8 @@
     "seekout": "^1.0.1"
   },
   "devDependencies": {
+    "babel-preset-es2015": "^6.5.0",
+    "babel-register": "^6.5.2",
     "mocha": "^2.4.5",
     "sinon": "^1.17.3"
   }