Fix deprecated warnings

all should work with Qt4.8 too, the replacements methods were already here.

added 7 commits

• 51200586...0eb6bd2f - 4 commits from branch master
• ec718191 - replace deprecated QTime with QElapsedTimer
• a2474ed0 - remove deprecated QString::null with QString()
• f8525b4e - fix dark/light by darker/lighter

Compare with previous version

enabled an automatic merge when the pipeline for f8525b4e succeeds

merged

mentioned in commit 4274861a