* add cc addresses and post_id to sent email logs
* sort cc addresses by email address filter value and collapse additional addreses into tooltip
* add slice helper for use in ember tempaltes
Follow up to 4d3c1ceb44b87d3bcb9c5eb2472d86b0cd2b2b0b, this commit
shows the SMTP response in the admin email sent list and also moves the
topic/post link into a new column. Reply key is now in its own column.
This reduces chances of errors where consumers of strings mutate inputs
and reduces memory usage of the app.
Test suite passes now, but there may be some stuff left, so we will run
a few sites on a branch prior to merging
