In python3, httplib has been renamed http.client.

When using python3, this fix imports http.client as httplib.
In python3, has_key has been deprecated for dictionaries.

Using the more pythonic, 'x' in dict instead.
In python3, the syntax for raising an excpetion has changed.

Using
    raise Excpetion("message")
instead of
    raise Excpetion, "message"
Revert httplib fix for python3.

This is taken care of by 2to3.
Merge pull request #83 from jwoillez/vizier-python3

Some python3 fixes to vizier
Fix python3 tests for simbad.
Merge pull request #88 from jwoillez/simbad_test_py3

Fix python3 tests for simbad.