clean up imports

blockstack/lib/hashing.py

@@ -21,15 +21,12 @@
     along with Blockstack. If not, see <http://www.gnu.org/licenses/>.
 """
 
-from utilitybelt import is_hex
 from binascii import hexlify, unhexlify
-import hashlib
 
 import virtualchain
 from virtualchain.lib.hashing import *
 
 from .b40 import b40_to_bin
-from .config import LENGTHS
 
 
 def hash_name(name, script_pubkey, register_addr=None):