[release] 0.3.3: Greenkeeper, Travis CI, Updated 📦️'s, eslint

📦️ Packages:
+ eslint@4.1.1
+ eslint-config-react-app@1.0.5
+ eslint-plugin-import@2.6.1
+ eslint-plugin-jsx-a11y@6.0.2

🌲️ GreenKeeper
> Added GK to help keep packages up to date

⛑️ Travis CI
> Added Travis to prepare builds / branches to be verified

📏️ eslint
> Updated rules throughout to be in-line with 4.x

🗓️ TODO:
> Add proper tests for post builds on Travis
> That will bump this up to 0.4.0, unless something else does beforehand

package.json

@@ -1,6 +1,6 @@
 {
   "name": "react-instafeed",
-  "version": "0.3.2",
+  "version": "0.3.3",
   "description": "Instafeed.js component for React",
   "author": {
     "name": "Jerome Fitzgerald",