got rid of 'numpy' dependency

Kirill V. Lyadvinsky · Kirill V. Lyadvinsky · commit 62b70c3a0d5c · 2016-05-19T10:59:59.000+03:00
diff --git a/requirements.txt b/requirements.txt
@@ -1 +0,0 @@
-numpy
diff --git a/zxtools/hobeta.py b/zxtools/hobeta.py
@@ -8,7 +8,6 @@
 import struct
 from collections import namedtuple
 import argparse
-import numpy
 
 from zxtools import CHUNK_SIZE
 
@@ -41,7 +40,7 @@ def calc_checksum(data):
     """ Calculate checksum for data """
     check_sum = 0
     for i, value in enumerate(data):
-        check_sum = numpy.uint16(check_sum + value*257 + i)
+        check_sum = (check_sum + value*257 + i) % 0x10000
     return check_sum
 
 
