TYP: check_untyped_defs io.sas.sasreader

pandas\io\sas\sasreader.py:75: error: Incompatible types in assignment (expression has type "SAS7BDATReader", variable has type "XportReader")
rebase as well need to sort out some import issues. closing to reduce queue for now

 @simonjayhawkins if you can merge master and merge on green.