Fixed floating image layout when typing in subsequent paragraph

Fixed floating image layout when typing in subsequent paragraph
Now makes use of max size for images and keeps the image size reasonable
Added original image size so can usually avoid reloading image when recomputing
cached bitmap size
Takes into account bottom of the last floating image so scrollbars are
set correctly
Original image size is shown in disabled size controls

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@71277 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775