Add continuous property infrastructure to VHAL

Implemented RecurrentTimer class that can be used in VHAL
implementations to trigger an event every X amount of time.
This make sense for continous properties.
Also added linkToDeath for VHAL listeners.

Test: unit tests added and ran

Change-Id: I4a2e0607ff6b15b3e7babbe3fbb9fff8d4e28838
11 files changed