#171 Levels tool should not open in a new window

[Beep6581]

The Levels tool opens in a window. This is bad news for people using KDE4 where inactive windows are darkened, because then we can't adjust appropriate levels since we can't see the image in its correct colors.

A few people will know that they can create a rule for Luminance-HDR to not use compositing and therefore not suffer from this issue, but this is just a workaround. The correct solution would be for you to change the Levels tool from being a window to being a panel (floating or whatnot).

Demonstration of problem:
http://i.imgur.com/G0C96rs.jpg
http://i.imgur.com/yITmdxh.jpg