v2.0.0-rc.28

New

• Directive: content can now accept a Promise for async content loading (docs)
• Directive: loadingClass and loadingContent options
• Popover: open-group class to keep multiple popovers open (see demos)
• v-close-popover: all modifier to close all the popovers in the page
• createTooltip and destroyTooltip are exported for manual JS usage

Fixed

• v-close-popover was unintentionally closing all the popovers in the page by default--now only the containing popover
• Popover misc fixes