Added option to edit the away status to ACP
Added option to edit the away status in MCP
Added possibility to duplicate a theme
Fixes comments
Merge branch 'upstream/feature'
Add registration date and last active time as mass mail criteria
Update "5 Latest Moderator Actions" no results message

In MyBB 1.6, we show "Sorry, there were no results found with the criteria you selected." in the Mod CP when there aren't any moderator logs in the database. This makes it sound like the moderator has performed an action when they haven't. To make it sound more friendly and understandable, I've added a new language string and template which displays "No moderator actions are currently logged." instead.
Update language strings for users browsing this forum/thread

As there's a colon suffix, there's no need to include the (s).
Clean up Javascript
Use `text-overflow: ellipsis` for session IP address

Due to the recent addition of IPv6 support the IP addresses of the administrators logged in will jump to a new line if they're using IPv6. To make this a little neater I've added `text-overflow: ellipsis` to the desktop and mobile classes, and given the <li> a title with the full IP address.
Fix bug with rating threads
Move debug summary to language/template systems
Add missing call to my_inet_ntop() in Mod CP
Add missing CSS class to text input
Clean up Javascript
Add `overflow-y: scroll` to body

This change makes sure that even if there isn't a need for a scrollbar, it will show anyway to prevent the page from snapping between clicks.
Optimize PNG images

Simply, I sent these through optipng without affecting the color or color depth. This reduced the total file size by ~17%.
Remove unused GIF images
Fixes #1853 Allow login via email and/or username with settings in the ACP
Porting performances changes from MyBB 1.6