[Lazarus] TScrollbar users

[Zeljko]

Hi all,
Today I've fixed longstanding bug with TScrollbar and max allowed 
position of thumb. http://bugs.freepascal.org/view.php?id=20127
Now , gtk2 (gtk lib >= 2.14), qt and win32 have unified behaviour.
Pls. test against lazarus trunk >= r52156 and see if there's some 
regression or problem since I want to merge those fixes into 1.6.2.

P.S: Carbon users feedback is badly needed (haven't touch anything on 
osx yet ... too far away from my mac machine till next sunday)

Thanks.

zeljko