Update the email_publish method to accept a to_email kwarg

This will allow the email_publish method to send emails for other parts
of the code (for example the pkgdb2_branch.py script).
Update the pkgdb2.lib.add_branch method to return an information message upon success and failure
Add logic to send a summary report by email after the branching has occurred
Add the possibility to print the report instead of sending it by email
Not having a package specified is not enough to not send the email
Commit after having added all the new branches
Output a little information message in pkgdb2_branch before sending the email
Save the new branch to the database as we create them
Remove the commit at the end now that we commit as we go
Now that we save messages for successes as well as failures, no questions about returning them
Let's not send ourself an email in case something goes south and we run the branching again