enable extension compilation

setup.py

@@ -118,8 +118,8 @@ setup(name = "unitex",
                              library_dirs=['/usr/local/lib'],
                              sources = ["extensions/_unitex.cpp"])],
       
-#       cmdclass = {
-#           "build": CustomBuild,
-#           "clean": CustomClean
-#       }
+       cmdclass = {
+           "build": CustomBuild,
+           "clean": CustomClean
+       }
 )