Fixed orbit SlideAnimation
The animation was using animate({margin: '0%'}) which would effectively animate the css margin property.
The intention was to animate the marginLeft or marginRight property (depending on ltr or rtl of document).
Merge branch 'orbit-slide-fix' of https://github.com/ziad-saab/foundation into ziad-saab-orbit-slide-fix
Merge branch 'master' of github.com:zurb/foundation