Extract a RandomPathPlacer prototype from Deep Forest (rP11444) and Schwarzwald (rP15327) duplication, refs #4805, #4804.
This allows creation of paths that are not linear nor sine-shaped like the PathPlacer, refs #892.
To mimic the per-tile path elevation randomization on Deep Forest, use a SmoothElevationPainter and it's randomization argument from rP20354.
Use vector algebra and the mapCenter getter, refs #4845, #4854.
git-svn-id: https://svn.wildfiregames.com/public/ps/trunk@20879 3db68df2-c116-0410-a063-a993310a9797