Esperanto/French translations

Hi Marcus, Salut Marcus,

I'm using PHPMailer for years, and just discovered that error messages can be translated (previously I used a module using PHPMailer).

I added the Esperanto translation, corrected typography (unbreakable spaces) and found that $PHPMAILER_LANG['authenticate'] is not used.

Best regards

Merci pour cette très utile bibliothèque !

Olivier