Fix extra dependencies (#211)

Remove duplicate dependencies to avoid errors in deps attribute, and regenerate the .par files.
diff --git a/rules_python/whl.py b/rules_python/whl.py
index 3e9d4f8..b397fe2 100644
--- a/rules_python/whl.py
+++ b/rules_python/whl.py
@@ -82,6 +82,8 @@
       the names of requirements from the metadata.json
     """
     # TODO(mattmoor): Is there a schema to follow for this?
+    dependency_set = set()
+
     run_requires = self.metadata().get('run_requires', [])
     for requirement in run_requires:
       if requirement.get('extra') != extra:
@@ -96,7 +98,9 @@
       for entry in requires:
         # Strip off any trailing versioning data.
         parts = re.split('[ ><=()]', entry)
-        yield parts[0]
+        dependency_set.add(parts[0])
+
+    return dependency_set
 
   def extras(self):
     return self.metadata().get('extras', [])
diff --git a/tools/piptool.par b/tools/piptool.par
index d40b0f0..49d1dad 100755
--- a/tools/piptool.par
+++ b/tools/piptool.par
Binary files differ
diff --git a/tools/whltool.par b/tools/whltool.par
index 8db7f14..07b40b3 100755
--- a/tools/whltool.par
+++ b/tools/whltool.par
Binary files differ