vcard: Base64 encoding breaks if object is binary: AttributeError: 'bytes' object has no attribute 'encode'

[pbiering]

vcard base64 encoding is broken

PHOTO;ENCODING=b;TYPE=JPEG:/9j/4AAQSkZ...

  File "/usr/lib/python3.4/site-packages/vobject/base.py", line 255, in serialize
    return behavior.serialize(self, buf, lineLength, validate)
  File "/usr/lib/python3.4/site-packages/vobject/behavior.py", line 162, in serialize
    out = base.defaultSerialize(transformed, buf, lineLength)
  File "/usr/lib/python3.4/site-packages/vobject/base.py", line 993, in defaultSerialize
    child.serialize(outbuf, lineLength, validate=False)
  File "/usr/lib/python3.4/site-packages/vobject/base.py", line 255, in serialize
    return behavior.serialize(self, buf, lineLength, validate)
  File "/usr/lib/python3.4/site-packages/vobject/vcard.py", line 227, in serialize
    VCardTextBehavior.serialize(obj, buf, lineLength, validate)
  File "/usr/lib/python3.4/site-packages/vobject/behavior.py", line 162, in serialize
    out = base.defaultSerialize(transformed, buf, lineLength)
  File "/usr/lib/python3.4/site-packages/vobject/base.py", line 1001, in defaultSerialize
    obj.behavior.encode(obj)
  File "/usr/lib/python3.4/site-packages/vobject/vcard.py", line 152, in encode
    line.value = codecs.encode(line.value.encode(coding), "base64").decode("utf-8")
AttributeError: 'bytes' object has no attribute 'encode'

[wpercy]

resolved by #49