Add additional fonts to WYSIWYG

Hi Simon, we are unable to add Open Sans to the list of fonts as that would affect everyones account.

I never like my clients to have the option of selecting fonts - they'll probably mix and match different fonts thinking it looks good. So I generally keep this feature turned off and apply different fonts to certain tags. For example in my CSS I may set all heading tags to use Georgia but the rest of the copy may be set to Arial. I would suggest doing something like this if possible.