Added "JRememberMe_" prefix

Add a prefix ("JRememberMe_" in this case, can be anything else but it's best to standardize it) to the cookie name set by the "remember me" functionality for user logins in Joomla.

Using a prefix in that cookie name instead of just a hashed UA string (as it's currently done), we can use Joomla in conjunction with web caching proxies like Varnish without having the "remember me" functionality broken.

plugins/system/remember/remember.php

@@ -51,7 +51,7 @@ public function onAfterInitialise()
 		// Check for a cookie if user is not logged in
 		if (JFactory::getUser()->get('guest'))
 		{
-			$cookieName = JUserHelper::getShortHashedUserAgent();
+			$cookieName = 'JRememberMe_'.JUserHelper::getShortHashedUserAgent();
 
 			// Check for the cookie
 			if ($this->app->input->cookie->get($cookieName))
@@ -77,7 +77,7 @@ public function onUserLogout($user, $options)
 			return true;
 		}
 
-		$cookieName = JUserHelper::getShortHashedUserAgent();
+		$cookieName = 'JRememberMe_'.JUserHelper::getShortHashedUserAgent();
 
 		// Check for the cookie
 		if ($this->app->input->cookie->get($cookieName))