Add new config options 'timestamp_subject', 'timestamp_subject_separator' and 'timestamp_mask'
If enabled, append a timestamp to the contact email's subject
Add the ability to specify a Timestamp to be appended to all sent email subject lines
Add @TODO - Is there a Factory\DI Container that can be used instead of statically constructing a Swift_Message object
Merge the latest development changes
 * Allow a timestamp to be appended to the email subject line
 * development comments/TODOs