Unwrap promises when setting a belongsTo
Merge pull request #2288 from emberjs/promiseUnwrap

Unwrap promises when setting a belongsTo
Add support for rollback of relationships from deleted state

Building upon #2208 and #2260 this commit enables reconnecting relationships
so we can rollback the relationship state from a deleted record

fixes #2036 fixes #1824 fixes #2010 fixes #1922
Implemented rollbacking of implicit relationships
Update recordArrays when record has reloaded
Fix jshint
Update tests on filters returning reloaded objects
Remove es3 rule in .jshintrc
Make JSLint happy
temporarily disable beta and canary
Refactor relationships with links