More DS.Adapter and DS.RestAdapter docs
Prevent resolution of jQuery's self fulfilling jqXHR thenable
Since it resolves on another turn, it will cause needless and unwrappable auto-runs

Related: https://github.com/emberjs/ember.js/issues/3051
Fix typo
Merge pull request #1101 from bradfol/doc-typo

Fix typo in Adapter docs
`save` method is not private
Merge pull request #1102 from bradfol/doc-fix

`save` method is not private