Extracted find functionality from the create method

- Created a new model.find method, which will attempt to find a model
in the model.all collection whioch matches the supplied attributes
- Updated create method to use the find method internally
Changed module definition style to also include AMD (RequireJS etc)
Merge branch 'extract-find-from-create' into sembr
Added associate and dissociate events.
Added 'chain' option for one() and many() to allow them to return the association, rather than chain themselves.