As requested on irc, and another common IDE has it at the same place. I
wonder whether we should have more options in that context menu. I
mainly put this in, because we don't have a good way to copy that full
path and I don't see a particular nice way to add it. Though I dislike
that it is only available in the context menu.

In it: Close Editor, Close Other Editors except me, Close All Editors.

Task-Nr: 256275

We are after all a text editor on steroids. That is people might want to
edit text files that don't have a ending we know.

Simply do it.

Task-Nr: 254558

It was only used for the watch-QImage-while-it-is-being-drawn-on feature,
which does not seem overly useful.

Each calls to fetchMore() was triggering an updateWatchData, and that
can happen several times per user interaction.

Instead of maintaining a list of sessions in our settings, simply list
all the files that we find.
Note: This will probably ressurect a few lost sessions for some people.

Task-Nr: 255140

Task-Nr: 255922

Best effort only though. This can make detection in the debugger which
engine should be used easier.

Task-Nr: 256161

I'm not 100% positive that this is the best fix. Though i can't come up
with a better one for the moment.

Task-Nr: 256251