Initial segwit support (testnet only)

lib/mnemonic.py

@@ -159,7 +159,9 @@ class Mnemonic(object):
         i = self.mnemonic_decode(seed)
         return i % custom_entropy == 0
 
-    def make_seed(self, num_bits=128, prefix=version.SEED_PREFIX, custom_entropy=1):
+    def make_seed(self, seed_type='standard', num_bits=128, custom_entropy=1):
+        import version
+        prefix = version.seed_prefix(seed_type)
         # increase num_bits in order to obtain a uniform distibution for the last word
         bpw = math.log(len(self.wordlist), 2)
         num_bits = int(math.ceil(num_bits/bpw)) * bpw