choose qt4 or qt5 automatically

I totally messed up my forked repository as I did not know how rebasing works so that I deleted it on github and created a new fork. But I think I understood the process now.

But how do I go back to your master branch after doing changes on mine? I tried to do `git fetch upstream`(where upstream is your repo). I am kind of new to this collaborative working with git.
it looks like these lines got left in and/or duplicated?