Add docs for dynamic finders.
Remove order conditions from dynamic finders.

Dynamic finders no longer support ordering.
Add section for behaviors.
Add event listeners section.
Add events docs.
Update docs for latest changes to dynamic finders.
Fix mistake.
Add reference to map-reduce section that will soon be written.
Update event docs.
Merge pull request #918 from cakephp/3.0-orm-part4

3.0 orm part4