Add Recording modes

Add Recording modes

Adds APIs for setting modes. It serves to select mode for recording what user want.
Mode means how to stream recorder works.

[apis]
streamrecorder_set_mode(streamrecorder_h recorder, streamrecorder_mode_e mode);
streamrecorder_get_mode(streamrecorder_h recorder, streamrecorder_mode_e* mode);

[modes]
Add stream recording modes.
- STREAMRECORDER_MODE_STREAM_BUFFER
- STREAMRECORDER_MODE_DEVICE_LOOPBACK

*STREAMRECORDER_MODE_STREAM_BUFFER
: Uses Stream Recorder same as current.

*STREAMRECORDER_MODE_DEVICE_LOOPBACK
: For using it only device's own screen (display) and audio, please use this mode.

Change-Id: Ibbe4356589769659e5091c1b57945ead837a5d22
Signed-off-by: Hyunsoo Park <hance.park@samsung.com>