Updating tests to fail for syncDirty  when a custom ID is used
Updating syncDirty so that it supports custom IDs
Removing a stray console.log
Make style consistent with codebase

- Space after :
- Files end in \n
- ClassCase for class names
Update Changelog
Merge pull request #95 from bsalinas/master
check for null in Store.exists
Merge branch 'master' of github.com:nilbus/Backbone.dualStorage

* 'master' of github.com:nilbus/Backbone.dualStorage:
  Update Changelog
  Make style consistent with codebase
  Removing a stray console.log
  Updating syncDirty so that it supports custom IDs
  Updating tests to fail for syncDirty  when a custom ID is used
test added for empty, started adding test for error after success