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`
I can't seem to reproduce this. Is the error coming from handlebars-v1.3.0.js? Does it happen to have a stacktrace?