Clickover plugin not compatible with bootstrap 3

The [clickover](https://github.com/lecar-red/bootstrapx-clickover) plugin has not been updated in a year and is not compatible with bootstrap 3. (See, e.g. #3424)
Wouldn't the logic be better if we did:

```
// If the click was inside of the popover, don't do anything
...
// Otherwise, close the current popover
...
```

I think that also removes the need to keep track of the previous popover