Update blog example to current versions

Updates:
Ember to 1.7.0 (from 1.5.0)
emberFire to latest
Handlebars to 1.3.0 (from 1.2.1)
Firebase to 1.1.0

Changes:
Replace findAll with find
Merge pull request #140 from dstaley/updated-blog-example

Update blog example with up-to-date libraries