Declaration of two further properties and test for non-existent $fromName

Updates to define two properties that were previously auto-defined. This is needed for current and future versions of php.
And a test to handle better the situation where the caller defined the mail From: value to be just an email address. __

SendOauth2A:
Define property $do_not_reply (previously auto-defined).
Test $mailFrom after parsing to see if $fromName exists ("" if not)

_SendOauth2D
Define property $SMTPAddressDefault (previously auto-defined)