chore(build): Migrate remaining tasks under build.js.dev to broccoli.

tools/broccoli/traceur/index.js

@@ -48,6 +48,7 @@ var TraceurFilter = (function (_super) {
             });
         });
     };
+    TraceurFilter.RUNTIME_PATH = traceur.RUNTIME_PATH;
     return TraceurFilter;
 })(Writer);
 module.exports = TraceurFilter;

tools/broccoli/traceur/index.ts

@@ -8,7 +8,7 @@ var xtend = require('xtend');
 
 class TraceurFilter extends Writer {
   constructor(private inputTree, private destExtension: string = '.js', private options = {}) {}
-
+  static RUNTIME_PATH = traceur.RUNTIME_PATH;
   write(readTree, destDir) {
     return readTree(this.inputTree)
         .then(srcDir => {