chore: add travis ci and commitizen config

Configures Travis with old node, LTS node, and latest node.

.travis.yml

@@ -0,0 +1,23 @@
+sudo: false
+language: node_js
+cache:
+  directories:
+    - node_modules
+notifications:
+  email: false
+node_js:
+  - '6'
+  - '4'
+  - '0.12'
+before_install:
+  - npm i -g npm@^2.0.0
+before_script:
+  - npm prune
+after_success:
+  - 'curl -Lo travis_after_all.py https://git.io/travis_after_all'
+  - python travis_after_all.py
+  - export $(cat .to_export_back) &> /dev/null
+  - npm run semantic-release
+branches:
+  except:
+    - /^v\d+\.\d+\.\d+$/

package.json

@@ -1,6 +1,5 @@
 {
   "name": "decaffeinate-traverse",
-  "version": "1.0.0",
   "description": "Traverse programs parsed using decaffeinate-parser.",
   "main": "dist/decaffeinate-traverse.js",
   "jsnext:main": "dist/decaffeinate-traverse.mjs",
@@ -9,11 +8,12 @@
     "build": "./script/build && rollup -c",
     "preflow": "npm run build",
     "flow": "flow check",
-    "test": "mocha"
+    "test": "mocha",
+    "semantic-release": "semantic-release pre && npm publish && semantic-release post"
   },
   "repository": {
     "type": "git",
-    "url": "git+https://github.com/decaffeinate/decaffeinate-traverse.git"
+    "url": "https://github.com/decaffeinate/decaffeinate-traverse.git"
   },
   "keywords": [
     "decaffeinate",
@@ -40,13 +40,20 @@
     "babel-register": "^6.9.0",
     "babelrc-rollup": "^1.1.0",
     "babylon": "^6.8.1",
+    "cz-conventional-changelog": "^1.1.6",
     "decaffeinate-parser": "^1.3.0",
     "flow-bin": "^0.27.0",
     "mocha": "^2.5.3",
     "rollup": "^0.31.2",
-    "rollup-plugin-babel": "^2.5.1"
+    "rollup-plugin-babel": "^2.5.1",
+    "semantic-release": "^4.3.5"
   },
   "publishConfig": {
     "registry": "https://registry.npmjs.org/"
+  },
+  "config": {
+    "commitizen": {
+      "path": "./node_modules/cz-conventional-changelog"
+    }
   }
 }