优化工单模块，增加企微模块

sg_wechat_enterprise/we_api/crypto/pkcs7.py

@@ -0,0 +1,23 @@
+# -*- coding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
+from wechatpy.utils import to_binary, byte2int
+
+
+class PKCS7Encoder(object):
+    block_size = 32
+
+    @classmethod
+    def encode(cls, text):
+        length = len(text)
+        padding_count = cls.block_size - length % cls.block_size
+        if padding_count == 0:
+            padding_count = cls.block_size
+        padding = to_binary(chr(padding_count))
+        return text + padding * padding_count
+
+    @classmethod
+    def decode(cls, decrypted):
+        padding = byte2int(decrypted[-1])
+        if padding < 1 or padding > 32:
+            padding = 0
+        return decrypted[:-padding]