Update CHANGELOG.md
Merge pull request #2607 from zeppelin/patch-2

Update CHANGELOG.md
Update changelog to correct Ember Data versions

0.1.3 was released with beta 11, updated to beta 12 in master
Merge pull request #2609 from ntodd/patch-1

Update changelog to correct Ember Data versions
Pull server files from http-{mock,proxy} into their own blueprint

Fixes #2356