Add comments to the clock API

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Add documentation to the event-field API

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Add documentation to the event type API

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Add documentation to the Event API

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Add documentation to the stream API

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>