IE11 browser detection and fixes

[KingSky]

IE11 gets along pretty well with vB3, though file downloads get a bit wonky due to some changes in how IE is detected.

In includes/functions.php find:

// detect macintosh 

Add above:

// Detect Modern IE11+
        if (strpos($useragent, 'trident') !== false AND !$is['opera'] AND !$is['ie'])
        {
            preg_match('#rv:([0-9\.-]+)#', $useragent, $regs);
            $is['ie'] = $regs[1];
 
        } 

Next, find:

if (strpos($useragent, 'gecko') !== false AND !$is['safari'] AND !$is['konqueror']) 

And replace it with

if (strpos($useragent, 'gecko') !== false AND !$is['safari'] AND !$is['konqueror'] AND !$is['ie'])