Merge pull request #11047 from mattwire/CRM-21244_setting_to_disable_sending_from_con...

CRM-21244 Enhancements to "FROM email addresses"

diff --cc CRM/Contribute/BAO/Contribution.php
Simple merge

diff --cc CRM/Contribute/Form/Contribution.php
Simple merge

diff --cc CRM/Mailing/BAO/Mailing.php
Simple merge

diff --cc CRM/Member/Form/Membership.php
Simple merge

diff --cc templates/CRM/Contribute/Form/Contribution.tpl
Simple merge