Upgrade LEAN Python to 3.6 from 2.7

- Adds log to display the python version the algorithm is using.
- Fixes python algorithms that were failing because of small subtleties
like leading zeroes.
- Updates pythonnet with a version compiled with python 3.6 flags

- Changes in DockerfileFoundation: we now use miniconda to manage the python
environment.
- Took the opportunity to add NTLK (#1349), Tensorforce (#1369) and
PyTorch/Pyro (#1385).
- Changes readme in Algorithm.Python to show steps to install miniconda

Algorithm.Python/BasicTemplateOptionsHistoryAlgorithm.py

@@ -69,7 +69,7 @@ class BasicTemplateOptionsHistoryAlgorithm(QCAlgorithm):
                     contract.ImpliedVolatility))
 
     def OnSecuritiesChanged(self, changes):
-        if changes == SecurityChanges.None: return
+        if changes == None: return
         for change in changes.AddedSecurities:
             history = self.History(change.Symbol, 10, Resolution.Hour).sort_index(level='time', ascending=False)[:3]