add auto-completion to embedded editor

[avilleret]

Qt has autocompletion tool which is pretty easy to setup : http://doc.qt.io/qt-5/qtwidgets-tools-customcompleter-example.html

KDE's one is more powerful but harder to build on windows and Mac OS : https://api.kde.org/frameworks/ktexteditor/html/

[jcelerier]

I've ported everything to https://github.com/Megaxela/QCodeEditor

which supports completion:

https://github.com/Megaxela/QCodeEditor/blob/master/example/src/MainWindow.cpp

if someone wants to look into it, that's an easy task and I can do some walkthrough in the code

[jcelerier]

@thibaudk wanna work on this ? as maybe if we end up having SC, having good auto-completion would be good too !

[thibaudk]

Sure ! It is also related to #1061