Add initial webhook support.

Signed-off-by: François de Metz <francois@stormz.me>
Add webhook activated?.

Signed-off-by: François de Metz <francois@stormz.me>
Update webhooks properties to be undescored.

Signed-off-by: François de Metz <francois@stormz.me>
Merge pull request #65 from francois2metz/webhooks

Add support of webhooks