Remove babel-preset-es2015 (#50)

* fix(build): fix targets in babel-preset-env config

Author: neolitec

.babelrc

@@ -2,7 +2,7 @@
   "presets": [
     ["env", {
       "targets": {
-        "browsers": ["last 2 versions", "ie 11"]
+        "browsers": ["last 9 versions", "ie >= 10"]
       }
     }],
     "stage-2"

package.json

@@ -20,7 +20,6 @@
     "babel-plugin-lodash": "^3.2.11",
     "babel-plugin-transform-runtime": "^6.15.0",
     "babel-preset-env": "^1.6.1",
-    "babel-preset-es2015": "^6.24.1",
     "babel-preset-stage-2": "^6.22.0",
     "babel-register": "^6.18.0",
     "bootstrap": "^3.3.7",