update gantry to v4.1.9

Release Notes - Gantry Joomla Framework - Version 4.1.9

Bug
• strict standards in /overlays.php
• remove isis dropdown setting
• Backward Compatibility: Title spans breaking K2 "Edit item" button
• custom logo dimensions display issue
• frontend editor image options alignment
• frontend editor publishing options alignment
• frontend editor article popup issue
• frontend editor image popup issues
• frontend editor readmore button styling issue
• archived articles filter background issue
• article info icon issue on archived articles page
• featured contacts styling issue
• archived articles filter button alignment
• Enabling RokBooster shows incorrect image in the breadcrumbs
• iphone page not rendering on first view by iphone
• Minor "assignments" tab alignment issue in Chrome 26