Better user tagging
1. Tag many users at once with @user_group syntax.
2. Tagged users will receive alerts and emails (system and user control)
*. This version of the add-on DOES NOT support XenForo 1.2 and below.
1. Upload files/directories under `upload` to your XenForo's root
2. Import add-on xml
3. Configure user group permission: "[Tag Me] Tag group" and make sure "Is taggable" is checked for target user groups.