Update blog example with up-to-date libraries

Updated Libraries:
Ember 1.5.0 => 1.7.0
emberFire => latest
Handlebars 1.2.1 => 1.3.0
Firebase => 1.1.0

Changes:
Replace `findAll` with `find`
Nevermind, this was my mistake. All looks good now! I have one comment on your other PR and then I'll merge them both.