`find` and `findAll`

[lmiller1990]

• in VTU beta these can be called with find(Component)
• this is not supported here (yet)
• should we support this? There are known limitations, at least in VTU beta and Vue 2 (cannot find functional components, Vuetify components, see here Some stubbed Vuetify components can't be found with find wrapper method vue-test-utils#1272 )
• how should this API look?

[lmiller1990]

For alpha 0 we will support the querySelector syntax only (cannot find a component/ref/name). find/findAll will return a DOMWrapper(s).

It should be able to find the ROOT node(s). eg:

<template>
  <div class="foo" />
  <div class="foo" />
  <div id="bar" />
</template>

• wrapper.find('.foo') will return a DOMWrapper
• wrapper.findAll('foo') will return an array of DOMWrapper
• wrapper.find('#bar') will return a DOMWrapper

[dobromir-hristov]

For this to work as we intend, I would need #25 to be merged.