Updates DB.define() and Model.get() to support tables with multiple primary keys (#135)
Adds support for Model.get([ key1, key2, .. ]) instead of Model.get(key1, key2, ..) (#135)
Fixes indentation on Instance.validate()
Passes model keys to instances on creation
Updates instance.save() to check for multiple keys
Updates instance.remove() to check for multiple keys
Changes instance autoSave to check for multiple keys
Changes instance initialization to add the multiple keys as properties instead of id
Updates a few more parts of instance to avoid looking at opts.id and look at opts.keys
Lints postgres driver
Updates instance to pass keys to driver.insert() instead of id

Redshift and SQLite are missing
Fixes typo in postgres driver variable name, changes code to look for id_prop = null
Updates redshift driver to try to support multiple keys
Removes console.log from mysql driver update method
Adds first test for multi key model
Updates Model.sync() to use keys instead of id on all drivers
Fixes sqlite DDL when using one primary key
Removes console.log from mysql DDL
Changes ChainFind.count() to avoid passing opts, no need
Updates Model.exists() for multikey