Import Magento Release 1.9.1.0
Merge remote-tracking branch 'magento-mirror/magento-1.9' into magento-lts-1.9

Conflicts:
	downloader/lib/Mage/Connect/Backup.php
	downloader/lib/Mage/Connect/Packager.php
	downloader/lib/Mage/HTTP/Client/Curl.php
	lib/Zend/Xml/Security.php