two bugfixes: 1. nist256p1.c was not included in setup.py, causing import errors when using TrezorCrypto.so in Python. 2. if you attempted a hardened derivation in python using the compiled TrezorCrypto module, an IntegerOverflowError would occur because Python ints are always signed. one-line fix by changing int to unsigned int in the pyx file

TrezorCrypto.pyx

@@ -1,6 +1,5 @@
 cimport c
 cimport cython
-
 cdef class HDNode:
 
 	cdef c.HDNode node
@@ -34,7 +33,7 @@ cdef class HDNode:
 		c.hdnode_public_ckd(cython.address(x.node), i)
 		return x
 
-	def private_ckd(self, int i):
+	def private_ckd(self, unsigned int i):
 		x = HDNode(copyfrom=self)
 		c.hdnode_private_ckd(cython.address(x.node), i)
 		return x

setup.py

@@ -5,6 +5,7 @@ from Cython.Build import cythonize
 from Cython.Distutils import build_ext
 
 srcs = [
+    'nist256p1',
 	'base58',
 	'bignum',
 	'bip32',