Make the text selection work almost correctly. Now it's possible to drag the mouse to select the text even for more than one page at once, like a text editor.
The next step about text selection is making it select char-by-char and not line-by-line as we do currently.

Finally, forwardported <a href="http://websvn.kde.org/?rev=569954">r569954</a>; fro trunk to make also this branch compile with a recent kdelibs.