Update README.rst
Acknowledge future.moves as a package
Update docs/quickstart.rst on standard library imports
Quick-start guide: describe urllib situation
Add a test for issue #47: "Contradictory terminology about native types"
Update porting cheat-sheet
Fix weirdly broken link to Overview page with the sphinx-bootstrap-theme
More doc tweaks
Improve the bytes_to_native_str() family of functions in future.utils

This fixes issue #47