Add proper window hints so that i3 doesn't try to tile popups

[KP2048]

not sure how fixable this is, but whenever a program running under cassowary opens a popup, my window manager, i3, says "ooh, new window, must tile!" and resizes all the windows and tiles it. this is mainly due to the window hints not being set on the rdp window becasue it is normally not a popup window, so it shouldn't float. but for popup windows, it obviously should float lol.