add failing unit test, setter_function.test.js
Merge branch 'test/setter_function' of https://github.com/ryanking8215/sequelize into ryanking8215-test/setter_function
fix bug where N:M association getters would not build instances with raw: true and therefor call attribute setters, closes #2201
Merge branch 'ryanking8215-test/setter_function'