Fix return errors.
More return type corrections.
More return fixes.
Add test for assertStatusCode and cleanup.
Merge pull request #5394 from cakephp/3.0-fixes

Fix return errors.
Merge pull request #5419 from cakephp/3.0-integrationtestcase

Add test for assertStatusCode and cleanup.
Remove non existant bake.

Bake has been moved to separate plugin
Always throw a 404

Account for the way that (array)null results in [] and not [null]
phpcs fix
Add InvalidPrimaryKeyException

Used with findOrFail when passed an invalid pk