Merge pull request #208 from ryvasquez/master

Use import Bitwise instead of use Bitwise

Author: devinus

lib/poison/encoder.ex

@@ -109,7 +109,7 @@ defimpl Poison.Encoder, for: Atom do
 end
 
 defimpl Poison.Encoder, for: BitString do
-  use Bitwise
+  import Bitwise
 
   @compile :inline
   @compile :inline_list_funcs