Remove bitcoin import that exposes confusing functions (#170)

* update dependencies

* Remove bitcoin import that results in exposing misleading functions

* fix local tests

* linting..

neocore/Cryptography/Helper.py

@@ -5,8 +5,6 @@
 Usage:
     from neocore.Cryptography.Helper import *
 """
-
-from bitcoin import *
 import os
 import time
 import random
@@ -19,6 +17,14 @@
 ADDRESS_VERSION = 23
 
 
+def random_key():
+    # Gotta be secure after that java.SecureRandom fiasco...
+    entropy = str(os.urandom(32)) + str(random.randrange(2 ** 256)) + str(int(time.time() * 1000000))
+    binary_data = bytes(entropy, 'utf-8')
+    x = hashlib.sha256(binary_data).digest()
+    return binascii.hexlify(x)
+
+
 def double_sha256(ba):
     """
     Perform two SHA256 operations on the input.

neocore/Cryptography/MerkleTree.py

@@ -1,3 +1,4 @@
+import sys
 from .Crypto import *
 from neocore.UInt256 import UInt256