This is the expected outcome, so explicitely reporting this, with
requiring the user to click a dialog box away, is kind of clutter.
This should solve issue #136.
It's rarely a good idea to overwrite files coming with a
distribution. Not for users, because they can't reset to factory
values; not for developers, because Git would pick up such changed
files.
Instead we read from configtool.default.ini now, but write to
configtool.ini. If configtool.ini is already present, it's
prefered over configtool.default.ini.