Add KiTTY support

[sebma]

Hi, can you please add a KiTTY output file (ini filetype in fact) when one clicks on the Get Scheme button ?

[ciembor]

I have very little time currently and the project may be tricky to set up on my new laptop (there are some native tools / libs from 10 years ago used to generate the app). But I will have it in mind, I hope I will find some time, maybe to rewrite the whole app. It's the most popular one I ever wrote.