6.0.0

I'm extremely stupid and didn't commit as I go. To anyone reading this
I'm extremely sorry. A lot of these changes are very broad and I plan on
releasing Babel 6.0.0 today live on stage at Ember Camp London so I'm
afraid I couldn't wait. If you're ever in London I'll buy you a beer
(or assorted beverage!) to make up for it, also I'll kiss your feet and
give you a back massage, maybe.

packages/babel-plugin-transform-inline-environment-variables/src/index.js

@@ -3,7 +3,7 @@ export default function ({ types: t }) {
     visitor: {
       MemberExpression(path) {
         if (path.get("object").matchesPattern("process.env")) {
-          var key = path.toComputedKey();
+          let key = path.toComputedKey();
           if (t.isStringLiteral(key)) {
             return t.valueToNode(process.env[key.value]);
           }