* Added a layout friendly constructor - it's not so nice to use, though, since
the original one already doesn't get a BRect (we just don't need the
resizing mode, and have to set the B_SUPPORTS_LAYOUT flag).
* Refactored size/frame computation a bit.
* Cleanup.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@28258 a95241bf-73f2-0310-859d-f6bbb57e9c96