Fix warning in rustc f09279395 2014-11-17.
Make ParseError a C-like enum.
Implement Error for ParseError
No flat enums. [breaking-change]
Dont transmute non-UTF-8 bytes to str, even though it kinda maybe looks safe.
Drop isindex support. We’ll see if anyone asks for it.
Make rust-encoding an optional feature.
Simplify and document the signature of EncodingOverride::encode.
Apprently "cannot" and "can not" are not identical.

https://github.com/servo/rust-url/pull/52#commitcomment-8664907