(core) create objectDropper in synchroniser
Description
The core design for frames and matrix flow treatment in sight is based on timelines. On one side, acquisition devices push data in timelines. A synchroniser grabbs than at some rate the data from the different timeline, and pushes the next data (frame, matrix, ...) to the different service which can do there treatment.
Up to now the synchroniser does not support frame dropping features. This is presently implemented only specifically in each service which require it, while it is highly time processing related.
Proposal
Add a new service that takes a group of objects as input and skip the modified signal according to the drop parameter in the XML configuration. This service should be used after the synchronizer, and allows to have a configurable frame drop, that can be shared among different services. Using several services, this also allows having different frame rates in the application.