Better Skype path finding and corrects font size in preview

Workaround for non standard Skype behaviour on <font size> : converts
sizes in typographic points for the mood preview
Partially fixes <font size> repeating twice when Return is pressed

QComboBox behaviour is inconsistent ! Manually entering the value and
selecting it with the mouse are managed by this code. However, selecting
an item in the list with the keyboard and then pressing enter to choose
it is still buggy and I can't do anything.