Add new method to DeviceInfo device type

- Add 'nyx_device_info_query' method to query device information
- Deprecate 'nyx_device_info_get_info' method
- Improve API documentation on DeviceInfo and OSInfo device types
- Set version to 5.1.0

[GF-2647] nyx-lib: Add "modern" query routine to device_info device type API

Open-webOS-DCO-1.0-Signed-off-by: Pekka Ropo <pekka.ropo@palm.com>

Change-Id: Ia49626851e9edc259896afbaeb72bc77a963a2a9