ENYO-1712: cleanup ServiceRegistry

- Send-out only one onServicesChange event per reload, instead of one
  at each configuration step of each service.
- Do not include non-instantiated services in onServicesChange event.

Enyo-DCO-1.1-Signed-off-by: Francois-Xavier KOWALSKI <francois-xavier.kowalski@hp.com>
ENYO-1712: cleanup ServiceRegistry (indentation)

Enyo-DCO-1.1-Signed-off-by: Francois-Xavier KOWALSKI <francois-xavier.kowalski@hp.com>