api cleanup
snap floating dock frames when near one another
add linked and unlinked button bitmaps
add a checkable bitmap button class
minor code cleanup
add a link button to the dock window
add a link button to the title bar
proxy the link button state
handle the link button in the title bar
move linked floating frames as a single unit
style the link buttons
Merge pull request #25 from nucleic/window-snapping-2

Window snapping 2