* develop-olympus: [ticket/7717] Localise default extension groups for attachments [ticket/9598] checkdnsrr() is now available on Windows with PHP 5.3 or later. Change if block order to always call checkdnsrr() if the function is available. [ticket/9173] No longer limit scope of numbers we store in the config table on [ticket/9536] Small improvement for query against user/session tables when managing users from the ACP. [ticket/9526] If an admin changes a user's 'user_allow_viewonline' flag to 'hide me' the admin usually wants that user to be hidden immediately. We therefore have to update his session if one exists. [ticket/9518] Correctly create new connection on PostgreSQL when new connection is forced. [ticket/9514] Correctly delete big datasets when deleting a forum including topics/posts on non-MySQL databases. [ticket/6726] Added localhost/127.0.0.1 note to database server hostname explanation in install language. [feature/remote_upload-filesize] Also check HTTP content-length before actually starting the file transfer. [feature/remote_upload-filesize] When transferring files from a remote webserver, abort the transfer as soon as the allowed filesize has been exceeded. [ticket/9176] Take current board timezone settings into account when setting board date format.