Increase Distiller version to 0.2.0-pre

Work on the 'master' branch uses pre-release version numbers.
After releasing v0.1.0 with PyTorch 0.3, we have upgraded 'master'
to support PyTorch 0.4 which contains API changes which are not
backward compatible.

distiller/__init__.py

@@ -35,7 +35,7 @@ del thinning
 #del policy
 
 # Distiller version
-__version__ = "0.1.0"
+__version__ = "0.2.0-pre"
 
 def model_find_param_name(model, param_to_find):
     """Look up the name of a model parameter.