update of api docstrings across coach and tutorials [WIP] (#91)

* updating the documentation website
* adding the built docs
* update of api docstrings across coach and tutorials 0-2
* added some missing api documentation
* New Sphinx based documentation

rl_coach/exploration_policies/parameter_noise.py

@@ -42,10 +42,18 @@ class ParameterNoiseParameters(ExplorationParameters):
 
 
 class ParameterNoise(ExplorationPolicy):
+    """
+    The ParameterNoise exploration policy is intended for both discrete and continuous action spaces.
+    It applies the exploration policy by replacing all the dense network layers with noisy layers.
+    The noisy layers have both weight means and weight standard deviations, and for each forward pass of the network
+    the weights are sampled from a normal distribution that follows the learned weights mean and standard deviation
+    values.
+
+    Warning: currently supported only by DQN variants
+    """
     def __init__(self, network_params: Dict[str, NetworkParameters], action_space: ActionSpace):
         """
         :param action_space: the action space used by the environment
-        :param alpha0:
         """
         super().__init__(action_space)
         self.network_params = network_params