Fix UnicodeDecodeError for Chinese

.travis.yml

@@ -8,7 +8,7 @@ python:
 - 3.5
 - 3.6
 install:
-- pip install pytz>=2010b six>=1.9.0
+- pip install CodeConvert>=2.0.5 pytz>=2010b six>=1.9.0
 - if [[ $TRAVIS_PYTHON_VERSION == 2.6 ]]; then pip install unittest2; fi
 script:
 - python test.py

bson/codec.py

@@ -19,6 +19,7 @@
 
 import calendar
 import pytz
+from CodeConvert import CodeConvert as cc
 from binascii import b2a_hex
 
 from six import integer_types, iterkeys, text_type, PY3
@@ -303,7 +304,7 @@ def decode_document(data, base, as_array=False):
             if PY3:
                 value = value.decode("utf-8")
             else:
-                value = unicode(value)
+                value = cc.Convert2Unicode(value)
             base += 4 + length
         elif element_type == 0x03:  # document
             base, value = decode_document(data, base)

setup.py

@@ -29,7 +29,7 @@ def run(self):
     name="bson",
     version="0.5.2",
     packages=["bson"],
-    install_requires=["pytz>=2010b", "six>=1.9.0"],
+    install_requires=["CodeConvert>=2.0.5", "pytz>=2010b", "six>=1.9.0"],
     author="Ayun Park",
     author_email="iamparkayun@gmail.com",
     description="BSON codec for Python",