fix email data binding, add test
clear contact media before update if the key is in the incoming data
clear all relevant media fields for contact on update
Merge pull request #177 from ali-graham/175_overwrite_contact_media_on_update

clear contact media before update if the key is in the incoming data
update CHANGELOG, prepare for 0.7.5 release
Merge pull request #176 from ali-graham/158_email_data_missing

fix email data binding, add test
prepare 0.7.6 for release