Add theano to optional_requirements.txt

optional_requirements.txt

 astropy
 lalsuite
 gwpy
+theano
\ No newline at end of file

tupak/core/sampler.py

@@ -1101,7 +1101,6 @@ class Pymc3(Sampler):
         if isinstance(self.priors[key], Sine):
             pymc3 = self.external_sampler
 
-            # import theano
             try:
                 import theano.tensor as tt
                 from pymc3.theanof import floatX