add es3-safe-transpile step

currently:

```js
promise.finally -> promise[‘finally’]
promise.catch   -> promise[‘catch’]
a.default       -> a[‘default’]
// and some more..
```

see: https://github.com/stefanpenner/es3-safe-recast for more
Included broccoli-asset-rev for fingerprinting.
Merge pull request #814 from rickharrison/broccoli-asset-rev

Included broccoli-asset-rev for fingerprinting in EmberApp
Ember-Data Beta 8
Merge pull request #855 from bcardarella/bc-ember-beta-data-8

Ember-Data Beta 8
Merge pull request #823 from stefanpenner/es3-safe

add es3-safe-transpile step
Do not watch node_modules/ember-cli/lib/broccoli.

This changes prevents changes in ember-cli/lib/broccoli/ from triggering
a rebuild.
Merge pull request #857 from rjackson/do-not-watch-ember-cli-broccoli-dir

Do not watch node_modules/ember-cli/lib/broccoli.