Clean out the lint trap.
algorithms: Add scheme support to rewrite_url.
compat.parse: Fix unquote_to_bytes.

unquote_to_bytes was broken when it was given a percent-encoded,
UTF-8 byte string.  It would return a UNICODE string containing
the bytes instead of a byte string.
url_tests: Use unicode_literals.
algorithms: Don't URL encode unnecessarily.
.gitignore: Ignore all environment directories.