Created by: vlki
When using latest Tether 1.3.1, which should be valid based on the ^1.1.1 dependency, calling "hide" two times in a row on tooltip after "show" ends up with tether#destroy() being called second time and error in Tether. Expecting that destroy should be called just once, I updated the code to be the case.
Test included. Minified Tether 1.3.1 added to test vendors. Without the fix the test fail in Chrome 50.0.2661.75, but not in PhantomJS 2.1.1.