Mixed case in the attributes

[Grégoire Castre]

The minLanguageId has a lowercased 'l' in the attributes while maxLanguageId is uppercased

Here : https://github.com/rxaviers/cldrjs/blob/master/src/core.js#L95

[Grégoire Castre]

Fixed by #40

[Rafael Xavier de Souza]

Thank you!