* moves the idea of the size of the item up to LayoutItem, as both Widget and Layout implemented it separately
* provides a way in LayoutItem to adjust a rect within an item to its margins (that is what LayoutItem::topLeft() is there for)
* fix several bugs, both painting and sizing, in LineEdit
* Applet sets margins now based on the existence of setDrawBackground
svn path=/trunk/KDE/kdebase/workspace/libs/plasma/; revision=776380
* introduce relayout() which does only that
* place guards around relayout() calls in Layout class to prevent recursion
svn path=/trunk/KDE/kdebase/workspace/libs/plasma/; revision=738923