refactor(deps): upgrade babel 7 (#17)

Upgrade to Babel 7

Author: azu

.babelrc

@@ -22,25 +22,18 @@
     "test": "test"
   },
   "scripts": {
-    "test": "mocha test/",
-    "build": "NODE_ENV=production babel src --out-dir lib --source-maps",
-    "watch": "babel src --out-dir lib --watch --source-maps",
+    "test": "textlint-scripts test",
+    "build": "textlint-scripts build",
+    "watch": "textlint-scripts build --watch",
     "prepublish": "npm run --if-present build"
   },
   "keywords": [
     "eslint",
     "textlint"
   ],
   "devDependencies": {
-    "babel-cli": "6.26.0",
-    "babel-preset-es2015": "6.24.1",
-    "babel-preset-jsdoc-to-assert": "4.0.0",
-    "babel-preset-power-assert": "2.0.0",
-    "babel-register": "6.26.0",
-    "eslint": "5.0.0",
-    "mocha": "5.2.0",
-    "power-assert": "1.6.0",
-    "textlint-tester": "4.1.3"
+    "eslint": "5.6.1",
+    "textlint-scripts": "^2.1.0"
   },
   "peerDependencies": {
     "eslint": "^3.0.0 || ^4.0.0 || ^5.0.0"