By teaching SwEditWin::KeyInput() about 2 vertical modes: the existing
tbrl one and the new btlr one. Up now correctly goes to the next
character and down to the previous one.

Change-Id: I71faebe62e5fa3892b37e8bea6c15d1fb84df5d1
Reviewed-on: https://gerrit.libreoffice.org/68183Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
Tested-by: Jenkins