Added dismissible alert styling
Added dismissible alert styling

Added missing `alert-dismissible` CSS class for improved styling:

http://getbootstrap.com/components/#alerts-dismissible
althaus/bootstrap-bundle,braincrafted/bootstrap-bundle,lashus/bootstrap-bundle,lashus/bootstrap-bundle,bigfoot90/bootstrap-bundle,bigfoot90/bootstrap-bundle,braincrafted/bootstrap-bundle,bigfoot90/bootstrap-bundle,lashus/bootstrap-bundle,althaus/bootstrap-bundle,braincrafted/bootstrap-bundle,althaus/bootstrap-bundle