Add six 1.7.3 for bootstrapping purposes. Ref #229

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branch : feature/issue-229
extra : source : 7e8095f69ea350cd04fabdbeca5c9733a57ec8ff
Add dependency on six

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branch : feature/issue-229
extra : source : dc7d411977b4b040ba82be2f5881a5723c0637d5
Use six for Python 2 compatibility

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branch : feature/issue-229
extra : source : 7b1997ececc5772798ce33a0f8e77387cb55a977
Regenerate egg_info

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branch : feature/issue-229
extra : rebase_source : 0a5b822d4e140229760b7f1b4e7ef29b45e6fb2f
Remove compat module

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branch : feature/issue-229
extra : rebase_source : 3b189d29653b1e8026f92d0c5e43c6e0bfd3bfcd
Try adding six as an egg for full compatibility with install_requires

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branch : feature/issue-229
extra : rebase_source : fb6ea5263750ad039250628e97d2f1cf6968fed3
Correct incorrect module for urllib.errors

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branch : feature/issue-229
extra : rebase_source : 93a1adbc64455d9cf7c3c8cceb7bbd283c06ac5b