but use integer coordinates. These are now used in ViewLayer for the
coordinate system (layout, scrolling offset, view bitmap layout)
* modest performance improvements by inlining some very often used
methods, and by preventing to go down the entire layer tree too often,
for example InvalidateScreenClipping was always called in the deep
mode, therefor it is save to assume that the tree does not have to
be traversed as soon as the clipping is already invalid
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@19390 a95241bf-73f2-0310-859d-f6bbb57e9c96
