attributes
- re-implemented the set_val to set them using the TLV buffer for an
attribute using DataModelProvider::WriteAttribute() API.
- renamed older set_val() to set_val_internal() and made it private.
- changed the set_val's occurances with set_val_internal inside the
component. Since our sdk should not be worrying about getting data
from the internally managed attributes, its safe to use the
set_val_internal().
- updated release notes