Synthetic handler is a sort of event delegation that allows placing
only one listener on the document to improve performance. It is an opt-in option.
Native listener places the listener on the node itself.
We re-add the possibility to validate props when dev mode is active.
No change in the API right Now. The dev mode is activated via the
configure method of App class.
The point is to have visibility on the development of the owl2 features.
This commit reintroduces some tests keeping them skipped in order to fulfill that purpose.
There still are some missing tests though.
Géry Debongnie