handle destroying widgets in thunks

* fix airgap for hasWidgets so that it's set on the parent of thunks if
  needed
* handle thunks when identifying widgets to be destroyed
use hasThunks rather than pre-rendering thunks
Merge pull request #18 from neonstalwart/widget-destroy

handle destroying widgets in thunks
fix package for vdom tests
0.0.22
Merge remote-tracking branch 'upstream/master'
Support hookEquals.