Change C++ class to C structure of functions for sensor devices

Change C++ class to C structure of functions for sensor devices

The hal interface between backend and api is changed to use C functions
rather than giving C++ object directly.
To accomplish that, codes are changed as below:
 * Functions for api calls are added
 * Device id is added to distinguish between the target sensor devices.
   Device id is required since it is hard to know which device should be
   used for a random api call.

Change-Id: Iaf474e4a7dfcb596995d95fb3bd96a25444d7c34
Signed-off-by: SangYoun Kwak <sy.kwak@samsung.com>