Make it crystal clear in documentation what this crate is supposed to do

[nox]

I don't see it written anywhere in the readme or in the crate description that UniCase is just for case insensitivity in the ASCII space, and not using Unicode case-folding.

[soc]

I experienced the same issue. This should really be fixed, probably by renaming the package.
Writing it in the documentation doesn't help much when you glance over the dependency tree cargo prints.

[seanmonstar]

I've been working on adding unicode case folding support. Something such as UniCase::new would support the full unicode range, and adding a UniCase::ascii which could use the faster ascii folding path.

[dashed]

Im guessing this is fixed by #14