added support for onChange report

Report is now notified when metric changes and updates reading values.

Tested:
- Added new unit tests
- OnChange report updates Readings when metric values cha

added support for onChange report

Report is now notified when metric changes and updates reading values.

Tested:
- Added new unit tests
- OnChange report updates Readings when metric values changes

Change-Id: I3be9ef7aa0486cb15bac627aa1de5cc632613b3b
Signed-off-by: Krzysztof Grobelny <krzysztof.grobelny@intel.com>

show more ...