add all the machine learning libraries

machine-learning.yml

 name: machine-learning
 channels:
   - conda-forge
+  - pytorch
 dependencies:
   # general numerics (version controlled)
   - python=3.6*
@@ -8,11 +9,19 @@ dependencies:
   - scipy=1.0*
   - kwant=1.3*
   - cython=0.28*
-  # fenics
-  - fenics=2017.2*
-  - mshr=2017.2*
   # general numerics (without version control)
   - anaconda
+  # machine learning
+  - pandas
+  - statsmodels
+  - scikit-learn
+  - theano
+  - tensor-flow
+  - keras
+  - pytorch
+  # NLP
+  - spacy
+  - nltk
   # plotting and serialization
   - deepdish
   - matplotlib=2.2*