Changing requires to install_requires, as that's the setuptools argument

Also removing sqlite3, as (as far as I understand) it's bundled with Python >= 2.5. https://docs.python.org/2/library/sqlite3.html

If we do want to include it for Python < 2.5, it looks like it should be included as pysqlite. Let me know if you think that should happen. https://github.com/ghaering/pysqlite