Add the ability to search both Serbian and Croatian simultaneously in the settings

[jugosever]

These standard languages are 100% mutually intelligible to each other, each with its own preferences; to not go deep into explanations, see this. I find myself jumping back and forth between Serbian and Croatian in the dictionary, so I'd like to propose a checkmark in the settings to allow searching both at the same time. I hope that's possible without much headache. As a side note, it would be also great if there was a setting for Serbian to be displayed in the Latin script.

Thanks, and cheers for this great application. :)