fix passing args down to super for sqa types
helpful error message if you pass an arg to type instead of field
Merge branch 'release_0.1.0' into feature/visitor
move run method to classmethod
fix issue with serializing dates when None
introduce type and field seperation for visitors
implement marshal_sqa as a visitor
WIP specific visitor for nested foreign key
make NestedForeignKey actually cater to every possible scenario!!!