Nice theme, but i made a mistake… 
I’ve done some editing in the theme options (Theme options → other->Code to display on Header)
I placed an image there, just to try… But when I deleted it, it stays at my page…
What can I do to reset the whole theme? Or to get rid of the image i placed here?
Thanks in advance!
I am aware of this issue and it will be addressed in the next theme update. I have already finished working on it and later today I will submit it for review at WordPress.org theme repository.
The code you placed inside Custom Scripts are written inside database and you have to remove it from there. You can use phpMyAdmin or other MySQL manager to find and remove this code. Otherwise just wait a day or so until theme will be available as automated update.
Sorry for my inconvenience.