Fix urlopen call in _fetch() for QuantumRandom.

[toffer]

This issue looks like it was fixed in 0.1.3 available from PyPI, but here's what the error looks like in the most recent version on Github (0.1.1):

$ python
Python 2.7.1 (r271:86832, Jul 31 2011, 19:30:53) 
[GCC 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import randomSources
>>> import pkg_resources
>>> pkg_resources.get_distribution("RandomSources").version
'0.1.1'
>>> rng = randomSources.QuantumRandom()
>>> rng.randrange(1, 7)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "randomSources/quantumRandom.py", line 152, in randrange
    return int(istart + self._randbelow(width, generator))
  File "randomSources/quantumRandom.py", line 174, in _randbelow
    r = self.getrandbits(k, generator)
  File "randomSources/quantumRandom.py", line 96, in getrandbits
    r |= generator.next()
  File "randomSources/quantumRandom.py", line 74, in cached_generator
    for n in self._fetch(dataType, cacheSize, cacheSize):
  File "randomSources/quantumRandom.py", line 62, in _fetch
    data = json.loads(urllib2.urlopen(url).read(), object_hook=object_hook)
NameError: global name 'urllib2' is not defined