[react-native] Replace jstransform with Babel in the OSS repo

Summary:
@public
Replaces jstransform with Babel. Additionally, stops (using the deprecated) passing an error property
back from the transformer, and instead passes an error in the first argument. This is because we were
able to update node-worker-farm to handle custom properties on errors.

Test Plan:
1. Export the oss project
2. npm install
3. Start the movies app
4. Make sure it works
5. Add a syntax error
6. Make sure the message is correct

packager/transformer.js

@@ -10,40 +10,37 @@
  */
 'use strict';
 
-var jstransform = require('jstransform').transform;
+var babel = require('babel');
 
-var reactVisitors =
-  require('react-tools/vendor/fbtransform/visitors').getAllVisitors();
-var staticTypeSyntax =
-  require('jstransform/visitors/type-syntax').visitorList;
-var trailingCommaVisitors =
-  require('jstransform/visitors/es7-trailing-comma-visitors.js').visitorList;
-
-// Note that reactVisitors now handles ES6 classes, rest parameters, arrow
-// functions, template strings, and object short notation.
-var visitorList = reactVisitors.concat(trailingCommaVisitors);
-
-function transform(srcTxt, filename) {
-  var options = {
-    es3: true,
-    sourceType: 'nonStrictModule',
+function transform(srcTxt, filename, options) {
+  var result = babel.transform(srcTxt, {
+    retainLines: true,
+    compact: true,
+    comments: false,
     filename: filename,
+    whitelist: [
+      'es6.arrowFunctions',
+      'es6.blockScoping',
+      'es6.classes',
+      'es6.destructuring',
+      'es6.parameters.rest',
+      'es6.properties.computed',
+      'es6.properties.shorthand',
+      'es6.spread',
+      'es6.templateLiterals',
+      'es7.trailingFunctionCommas',
+      'es7.objectRestSpread',
+      'flow',
+      'react',
+    ],
+    sourceFileName: filename,
+    sourceMaps: false,
+    extra: options || {},
+  });
+
+  return {
+    code: result.code,
   };
-
-  // These tranforms mostly just erase type annotations and static typing
-  // related statements, but they were conflicting with other tranforms.
-  // Running them first solves that problem
-  var staticTypeSyntaxResult = jstransform(
-    staticTypeSyntax,
-    srcTxt,
-    options
-  );
-
-  return jstransform(
-    visitorList,
-    staticTypeSyntaxResult.code,
-    options
-  );
 }
 
 module.exports = function(data, callback) {
@@ -54,15 +51,8 @@ module.exports = function(data, callback) {
       data.filename
     );
   } catch (e) {
-    return callback(null, {
-      error: {
-        lineNumber: e.lineNumber,
-        column: e.column,
-        message: e.message,
-        stack: e.stack,
-        description: e.description
-      }
-    });
+    callback(e);
+    return;
   }
 
   callback(null, result);