t2t-bleu to setup.py

now it can be installed through `python3 setup.py install`

Author: Gldkslfmsd

setup.py

@@ -24,6 +24,7 @@
         'tensor2tensor/bin/t2t-datagen',
         'tensor2tensor/bin/t2t-decoder',
         'tensor2tensor/bin/t2t-make-tf-configs',
+        'tensor2tensor/bin/t2t-bleu',
     ],
     install_requires=[
         'bz2file',