Restructuring a bit how the text-editor-like selection works:
* putting it in an own view mode
* associating the selection to every page
* using a better algorithm to calculate the selection, even in a page range
* moving its drawing from the page view to the page painter, so it's possibile to draw it just like it's done with eg annotations

Other changes (more or less related):
* moved the annotation popup to a better place, so it won't interfere with annotation drawing
* commented some debug code in TextPage