by setting up localVue with all required plugins (such as styleguide and vuex)
in a separate testSetup file we can avoid doing this individually in all component tests
the testSetup is executed before each test suite, so each test file gets a fresh
instance of localVue
This will allow us to use this.$scrollTo in components. I'm now also
using this in the mixin. With so many `this`s it gets horribly
difficult to properly test the mixin in isolation. So I decided to test
the mixin on the component directly.
