Fix scrollbar positioning

Tooltips will autoscroll when too big
Tooltip can be "locked" by pressing shift+l
Scrolling is "smoother" in long textzones or lists
Various misc UI improvments


git-svn-id: http://svn.net-core.org/repos/t-engine4@5405 51575b47-30f0-44d4-a5cc-537603b46e54