This is the first part of my rather large pull request here: [[ https://git.reviewboard.kde.org/r/130244/ | Revievboard ]]
It ports much of the code to the new signal/slot syntax, which makes it easier to spot errors during the rest of the porting process.
I changed some signal/slot names, because the new syntax doesn't handle overloads particularly well and added some new ones, because the new syntax doesn't handle default arguments at all.
Nothing too major, though.
This is the first time I created a revision with arcanist. I'm not sure it knows this is based on the kf5 branch. Let me know if I did anything wrong here.