WIP: typewriter annotation input: Replace QInputDialog by AnnotationWindow
Currently, a QInputDialog is used to let the user enter the initial content of FreeText or TypeWriter annotations. For later changes, an annotation window is opened. For consistency, this patch replaces the QInputDialog by an annotation window, too.
An additional advantage (for me at least), is that a multiline QInputDialog does not implement line wrapping, which makes it tedious to enter longer text.