hover+animation bug, multi tabs content show at once

To reproduce:
1. Use mouseevent : 'hover' and animation: true. 
2. quickly hover over the tabs
3. notice the animation causes multiple tab content to show at once. 
4. Reference Video: https://www.berrycast.com/conversations/76f04593-4edf-5d16-bb19-650e58b7a5a6

Code to reproduce issue:
`$('.tabs_hover').tabslet({
    mouseevent: 'hover',
	attribute: 'href',
	animation: true,
})`
