pybullet a bit more refactoring, moving around files.

pybullet: move data to pybullet_data package, with getDataPath() method

examples/pybullet/gym/pybullet_data/__init__.py

@@ -0,0 +1,6 @@
+import pybullet as p
+import os
+
+def getDataPath():
+	resdir = os.path.join(os.path.dirname(__file__))
+	return resdir