-[FEATURE] added possibility to not use a junction table for many-to-many associations on the same table (thanks to innofluence)
-[FEATURE] results of the `import` method is now cached (thanks to janmeier)
-[FEATURE] added possibility to check if a specific object or a whole bunch of objects is currently associated with another object (thanks to janmeier)
-[FEATURE] added possibility to globally disable adding of NULL values to sql queries (thanks to janmeier)
-[FEATURE] Model.create can now also be used to specify values for mass assignment (thanks to janmeier)
# v1.4.1 #
-[DEPRECATION] Added deprecation warning for node < v0.6.
