GUI update:
- Loading bar now takes coastline into consideration.
- Loading bar only vanishes when the map has been drawn. In the time in between, it will say "Drawing map. Please wait..."
- Help window added (new class: HelpWindow)
- MovableImage IS NOT USED.
- Shift + Right click pops a utility window up.
- Boolean isMap in MapPanel changed to drawMap (because it makes more sense).

To Johan:
- Draw shortest path implemented, but the getShortestPath in PathFinder does not return the correct array or ends up in a NullPointerException (when I checked, it was due to nodes.get(xy1). I suspect there is something wrong with the Graphs method.