osc: update plotting routine

use libiio1 stream object
use libiio1 API
re-enable plotting functions
TO DO: context clone and osc_test_value functions

Signed-off-by: Cristina Suteu <[email protected]>

Author: cristina-suteu

Diff for: datatypes.h

@@ -71,6 +71,7 @@ struct extra_dev_info {
 	char adc_scale;
 	gfloat **channels_data_copy;
 	GSList *plots_sample_counts;
+	struct iio_stream *stream;
 };
 
 struct buffer {