widget/ui documentation update.

git-svn-id: https://www.libavg.de/svn/trunk/libavg@8893 44470bb9-56e9-0310-a0f8-c586564d3dc6
Documentation spelling fixes.

git-svn-id: https://www.libavg.de/svn/trunk/libavg@8894 44470bb9-56e9-0310-a0f8-c586564d3dc6