* Also add equivalent methods to the layout builders in LayoutBuilder.h
* BSplitView now calls BControlLook::ComposeSpacing(), instead of BSplitLayout
* part of #7447
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@42077 a95241bf-73f2-0310-859d-f6bbb57e9c96