Applying patch from @tigrang for ensuring keys from all eagerly loaded
assocs
Implementing the logic in the Association class to create an empty
association value
Moving the code around so that each association type can customize it
Revarting parts of the previous commit, was not a good idea
Adding tests to show the key is present for a hasOne association usgin
select strategy
Merge pull request #3283 from cakephp/3.0-force-property

3.0 force property