lookup with extension-less file on Windows returns wrong type

[seanmonstar]

mime.define({ 'browserid': 'application/json' });

mime.lookup('/www/.well-known/browserid'); // application/json
mime.lookup('\\www\\.well-known\\browserid'); // application/octet-stream

This is because the regex matches well-known\\browserid. I can think of 2 fixes here:

1. Add a backslash to the regex: /.*[\.\/\\]/g
2. Or removing regexes, and relying on path: path.extname(file) || path.basename(file)