Fixed some redraw problems in InsetText/Tabular/Collapsable. Fixed problems

Fixed some redraw problems in InsetText/Tabular/Collapsable. Fixed problems
regarding automatic scrolling of Tabulars (still something wrong). Broken
MousePointer inside InsetText&co (hopefully easy to fix), but I still commit
so that people can have a look at it. It also should enhance speed of redraw
and minimize redraws (still some optimization possible).

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@1915 a592a061-630c-0410-9148-cb99ea01b6c8