Add info buttons to the input fields

[maxscheurer]

For non-intuitive input fields, let's implement kind of an Information system (like in QwikMD). We can make a subclass like:

class PicButton(QAbstractButton):
    def __init__(self, pixmap, parent=None):
        super(PicButton, self).__init__(parent)
        self.pixmap = pixmap

    def paintEvent(self, event):
        painter = QPainter(self)
        painter.drawPixmap(event.rect(), self.pixmap)

    def sizeHint(self):
        return self.pixmap.size()

and give it an info button icon... Then open a QMessageBox to display further information, citations, etc...

[maxscheurer]

Probably just messes up the nice GUI...