Add husky to prevent commit without green tests

package.json

@@ -15,7 +15,10 @@
   ],
   "main": "dist/lesspass.js",
   "module": "src/lesspass.js",
+  "repository": "lesspass/core",
   "scripts": {
+    "precommit": "npm test",
+    "prepush": "npm test",
     "build": "rimraf dist && npm run build:debug && npm run build:min",
     "build:debug": "webpack",
     "build:min": "cross-env NODE_ENV=production webpack -p",
@@ -36,6 +39,7 @@
     "babel-loader": "^6.2.10",
     "chai": "^3.5.0",
     "cross-env": "^3.1.4",
+    "husky": "^0.13.2",
     "karma": "^1.3.0",
     "karma-chai": "^0.1.0",
     "karma-chrome-launcher": "^2.0.0",