Changing the way eager loaded values are nested under each result.

The old way was making ResultSet confused about hydrating results having
the same association alias in the associaitons map
Fixing some failing tests
Adding joinData to the target relation array wehn using matching

The scenario that c41f40cd was wondering about came to be sooner than
expected.
Completing test for showing it is possible to use duplicate associaiton
alaises in contain
test file was .. misnamed :|
Add merge option to InstanceConfig trait

This addresses the problem raised in b81ebffe
merge by default
make config chainable
Don't merge events

This is one of the exceptions where merging is not likely to be the
desired behavior - it would mean that you can't configure to disable
default events, it'd require code calls
change proxied config function to return the helper

On write options to modify templates - return $this instead of the
templater object
correct constructor and write expectations
Updating function signature
Nitpicks
Merge pull request #3139 from cakephp/3.0-hydration-fixes

3.0 hydration fixes
Merge pull request #3134 from AD7six/3.0-form-auth-config-fix

Add possibility to merge config to InstanceConfigTrait