build: consolidate tsc to ease migration to @types/ based typings delivery

I actually tried to use @types/* directly but came across several issues which prevented me
from switching over:
- https://github.com/Microsoft/TypeScript/issues/8715
- https://github.com/Microsoft/TypeScript/issues/8723

tools/broccoli/broccoli-tree-stabilizer.ts

@@ -1,6 +1,3 @@
-/// <reference path="broccoli.d.ts" />
-/// <reference path="../typings/node/node.d.ts" />
-
 import fs = require('fs');
 let symlinkOrCopy = require('symlink-or-copy');