1.6 Rangefinder

First thanks to Starstrider42's initial commit for this feature.
Here are my changes:
- Added two new classes, `TargetInfoWindow` and `TargetInfoFragment`
- The AbstractWindow got a callback action `onPositionChanged` and will be triggered after dragging the window
- The AntennaFragment got two callback actions `onMouseOverListEntry` and `onMouseOutListEntry` they will be triggered if the mouse is over/out of a list entry by this fragment
- The AntennaWindow and FilterOverlay got the new `TargetInfoWindow` to show some informations to the target
- The first created `TargetInfoPopup`-file was deleted

Notice: I got some conflicts by merging the 3 month old code into the 1.6 branche. I hope I haven't made any mistakes :no_mouth: