py-bitarray: updated to 1.8.0

1.8.0:
* add `bitarray.util.serialize()` and `bitarray.util.deserialize()`
* allow whitespace (ignore space and `\n\r\t\v`) in input strings,
  e.g. `bitarray('01 11')` or `a += '10 00'`
* add `bitarray.util.pprint()`
* When initializing a bitarray from another with different bit endianness,
  e.g. `a = bitarray('110', 'little')` and `b = bitarray(a, 'big')`,
  the buffer used to be simply copied, with consequence that `a == b` would
  result in `False`.  This is fixed now, that is `a == b` will always
  evaluate to `True`.
* add example showing how to jsonize bitarrays
* add tests


(adam)