Make setup.py py3-compatible

Change-Id: I87ab31344e66fb32f604bca1cf76d6ff5cda7fd2
Use Py3-httplib2-compatible SSL Error handling

Change-Id: I0ed137df4158185f77e68c2e300a78eb5caf3733
Change Request from DictMixin to MutableMapping

Change-Id: Ieea4e11967642039dbe82cbadf26e90865153e9e
Use key function instead of comparator for sorting interwikis

Change-Id: Ic7cde6334eb9e07c2e550ef4e2c88a4ccd84f49b
Use bytes-based url (un)quote for py3k

Change-Id: I6f78e4e0ab25f47558b44e7053f6b9c7e29d3c15