Convert code to python 2.7 (#35)

* Convert code format to python2.7 (SAC)

* Convert code format python2.7 (TD3, all fD)

* Remove no use import and black setting

* Change SAC param

* Change env name Reacher-v2 to v1

* Remove old version reacher training script

* Convert code format python2.7

* Modify .travis.yml

* Add install command python3.6 & black on Makefile

* Fix seperator to tab on Makefile

* Modify Makefile

* Fix little error

* Change td3 gamma parameter

scripts/algorithms/common/noise.py

@@ -13,20 +13,14 @@ class GaussianNoise:
     Taken from https://github.com/vitchyr/rlkit
     """
 
-    def __init__(
-        self,
-        action_dim: int,
-        min_sigma: float = 1.0,
-        max_sigma: float = 1.0,
-        decay_period: int = 1000000,
-    ):
+    def __init__(self, action_dim, min_sigma=1.0, max_sigma=1.0, decay_period=1000000):
         """Initialization."""
         self.action_dim = action_dim
         self.min_sigma = min_sigma
         self.max_sigma = max_sigma
         self.decay_period = decay_period
 
-    def sample(self, t: int = 0) -> float:
+    def sample(self, t=0):
         """Get an action with gaussian noise."""
         sigma = self.max_sigma - (self.max_sigma - self.min_sigma) * min(
             1.0, t / self.decay_period
@@ -42,9 +36,7 @@ class OUNoise:
     ddpg-pendulum/ddpg_agent.py
     """
 
-    def __init__(
-        self, size: int, mu: float = 0.0, theta: float = 0.15, sigma: float = 0.2
-    ):
+    def __init__(self, size, mu=0.0, theta=0.15, sigma=0.2):
         """Initialize parameters and noise process."""
         self.state = np.float64(0.0)
         self.mu = mu * np.ones(size)
@@ -56,7 +48,7 @@ class OUNoise:
         """Reset the internal state (= noise) to mean (mu)."""
         self.state = copy.copy(self.mu)
 
-    def sample(self) -> float:
+    def sample(self):
         """Update internal state and return it as a noise sample."""
         x = self.state
         dx = self.theta * (self.mu - x) + self.sigma * np.array(