make restacking much better, yay

make restacking much better, yay

no more cludge using actions to raise windows. when a window changes layer it
uses add_nonintrusive now so it won't cover the focused window. this way
fullscreen windows when they drop down, don't cover up the new focus target.

fix add_nonintrusive so that if the window is focused it gets added to the top

add back support for ConfigureRequest restacking, this time properly though,
using all the detail and sibling modes. but when windows use this to raise they
are using some old business and we're going to assume they actually want to
activate instead. this means firefox works nicely. yay.

ubuntu's firefox has been made to just stop raising entirely though. !