Merge pull request markedjs#1020 from Feder1co5oave/lint

[linting] Use eslint to lint code + minor refactoring + Travis CI setup

.eslintrc.json

@@ -0,0 +1,27 @@
+{
+  "extends": "standard",
+  "plugins": [
+    "standard"
+  ],
+  "parserOptions": { "ecmaVersion": 5 },
+  "rules": {
+    "semi": "off",
+    "indent": ["warn", 2, {
+      "VariableDeclarator": { "var": 2 },
+      "SwitchCase": 1,
+      "outerIIFEBody": 0
+    }],
+    "space-before-function-paren": "off",
+    "operator-linebreak": ["error", "before", { "overrides": { "=": "after" } }],
+    "no-cond-assign": "off",
+    "no-useless-escape": "off",
+    "no-return-assign": "off",
+    "one-var": "off",
+    "no-control-regex": "off"
+  },
+  "env": {
+    "node": true,
+    "browser": true,
+    "amd": true
+  }
+}

.travis.yml

@@ -1,5 +1,16 @@
 language: node_js
 node_js:
   - "0.10"
-  - "0.8"
-  - "0.6"
+  - "4"
+  - "lts/*"
+  - "node"
+script: |
+  if [ `node --version | cut -d . -f 1,2` = "v0.10" ]; then
+    sed -i s/0o755/0755/ test/index.js;
+    npm test;
+  else
+    npm run lint && npm test;
+  fi
+cache:
+  directories:
+    - node_modules