1. change all gatt cb function to 3 args and function type. add gattc_if/gatts_if as second argument 2. delete gatt_if of "gatt cb param" 3. separate conn_id and gatt_if from conn_id 4. change the demo code as the gatt changed
1. cleanup the un-necessary include in api.h for "extern c" 2. add UUID define
