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-strict-mode/README.md

@@ -0,0 +1,35 @@
+# babel-plugin-transform-strict-mode
+
+TODO
+
+## Installation
+
+```sh
+$ npm install babel-plugin-transform-strict-mode
+```
+
+## Usage
+
+### Via `.babelrc` (Recommended)
+
+**.babelrc**
+
+```json
+{
+  "plugins": ["transform-strict-mode"]
+}
+```
+
+### Via CLI
+
+```sh
+$ babel --plugins transform-strict-mode script.js
+```
+
+### Via Node API
+
+```javascript
+require("babel-core").transform("code", {
+  plugins: ["transform-strict-mode"]
+});
+```

packages/babel-plugin-transform-strict-mode/package.json

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+{
+  "name": "babel-plugin-transform-strict-mode",
+  "version": "1.0.0",
+  "description": "TODO",
+  "repository": "babel/babel",
+  "license": "MIT",
+  "main": "lib/index.js",
+  "keywords": [
+    "babel-plugin"
+  ],
+  "dependencies": {
+    "babel-runtime": "^5.0.0",
+    "babel-types": "^6.0.0"
+  }
+}

packages/babel-plugin-transform-strict-mode/src/index.js

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+import * as t from "babel-types";
+
+export default function () {
+  return {
+    visitor: {
+      Program(path) {
+        let { node } = path;
+        
+        for (let directive of (node.directives: Array<Object>)) {
+          if (directive.value.value === "use strict") return;
+        }
+
+        path.unshiftContainer("directives", t.directive(t.directiveLiteral("use strict")));
+      }
+    }
+  };
+}