Layer/Model weights as R arrays

`get_weights(object, trainable = NA)`set_weights(object, weights)

- object
Layer or model object

- trainable
if

`NA`

(the default), all weights are returned. If`TRUE,`

- weights
Weights as R array

Other model persistence:
`model_to_json()`

,
`model_to_yaml()`

,
`save_model_hdf5()`

,
`save_model_tf()`

,
`save_model_weights_hdf5()`

,
`serialize_model()`

Other layer methods:
`count_params()`

,
`get_config()`

,
`get_input_at()`

,
`reset_states()`