Allow Import of the following civicrm_contact fields:
do not call,
do not email,
do not trade,
do not mail
prefered communication method
For the 4 boolean fields, use the same approach as we currently have for importing custom boolean (yes/no) fields ( I think the rule is 1=true and anything else = false - but please confirm and implement these with the same rules ).
Also - this change will make these fields available to Profile forms - so please test and correct any issues.