Revert "Add global Model event listeners"

This reverts commit 013fb67433de90f19b34c915022b294470411536.
Revert "Don't raise exception in Model.load when loading missing association"

This reverts commit a859a9d376ec077e4faffd8bfc6c6c7192fbec9f.
Revert "Add Model.find() and 'events' property to Model.subclass"

This reverts commit 1ed759daa8f325ebfb0f188419713c943e769fa2.
Revert "Trigger events when loading Model associations"

This reverts commit e2afee00c3237af0e997b2309061552dfb7a27a9.