The framework now supports watch() and unwatch(), which can be used
by the telemetry library to init events or pre-fetch fields when recording
starts.
* A new header file RdcTelemetryLibInterface.h is defined for library to
include it.
* The RdcWatchTable will not talk to RdcMetricFetcher directly anymore.
It will call the framework watch/unwatch to dispatch it to the libraries.
* Make the python binding consistent with the current code.
Change-Id: Ie5731d920ed5928f901369d60c23bd450807a562
Bill(Shuzhou) Liu
151520b97e