pickle support

[superbobry]

Hello, cyvcf seems to have the same problem as jamescasbon/PyVCF#108:

>>> import cyvcf
>>> import cPickle
>>> f = open(path)
>>> r = cyvcf.Reader(f)
>>> cPickle.dumps(next(r))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/user/.virtualenvs/bio-env/lib64/python2.6/copy_reg.py", line 70, in _reduce_ex
    raise TypeError, "can't pickle %s objects" % base.__name__
TypeError: can't pickle _Record objects