enable stable PD plugin in premake4.lua PyBullet

add a normalize in the setRotation axis/angle to be sure.
Add more code from the DeepMimic project, training doesn't work yet.

examples/pybullet/gym/pybullet_envs/deep_mimic/learning/nets/__init__.py

@@ -0,0 +1 @@
+from . import *

examples/pybullet/gym/pybullet_envs/deep_mimic/learning/nets/fc_2layers_1024units.py

@@ -0,0 +1,13 @@
+import tensorflow as tf
+import learning.tf_util as TFUtil
+
+NAME = "fc_2layers_1024units"
+
+def build_net(input_tfs, reuse=False):
+    layers = [1024, 512]
+    activation = tf.nn.relu
+
+    input_tf = tf.concat(axis=-1, values=input_tfs)          
+    h = TFUtil.fc_net(input_tf, layers, activation=activation, reuse=reuse)
+    h = activation(h)
+    return h

examples/pybullet/gym/pybullet_envs/deep_mimic/learning/nets/net_builder.py

@@ -0,0 +1,11 @@
+import learning.nets.fc_2layers_1024units as fc_2layers_1024units
+
+def build_net(net_name, input_tfs, reuse=False):
+    net = None
+
+    if (net_name == fc_2layers_1024units.NAME):
+        net = fc_2layers_1024units.build_net(input_tfs, reuse)
+    else:
+        assert False, 'Unsupported net: ' + net_name
+    
+    return net