Fixes Collection#set when no options are passed.
Adding similiar Node/NodeList reverse relation test that fails
Merge pull request #315 from elasticsales/failed-reverse-relation

Add a test case showing failing reverse relation
Check (and error on) duplicate ids when explicitly setting the idAttribute.

Closes #295
Also delete `options.collection` on set in `findOrCreate`. Fixes #315
Update changelog for master
test showing change events shouldn't fire too often
test: a collection parse function shouldn't break fetching of parent model
failing test: 'Deep reverse relation starting from a collection'
Adding similiar Node/NodeList reverse relation test that fails