Order of items in geohash.neighbors does not match documentation. #16

The documentation shows:

>>> geohash.neighbors('ezs42')
['ezefr', 'ezs43', 'ezefx', 'ezs48', 'ezs49', 'ezefp', 'ezs40', 'ezs41']

I get the following when I run the same line in OSX on python-geohash==0.8.4:

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

>>> geohash.neighbors('ezs42')
['ezefr', 'ezs43', 'ezs40', 'ezefp', 'ezs41', 'ezs48', 'ezefx', 'ezs49']

If the order is indeterminate a dict would be a better choice so that you could 
predictably get a specific neighboring geohash.