tson::Tile: Add getPosition() and getPosInTileUnits();

[ssbmtonberry]

tson::Tile: Add getPosition() and getPosInTileUnits();

[SSBMTonberry]

Actually solved this at the same time as issue #1 . Just forgot that I had an own issue for this.
There is one thing to keep in mind, though, and that is: The position from the getTileData() is still required. Reason being that the Tiles themselves are unique (there are only one of each), but they can be placed in several places. I might redesign this at a later point, but for now tileData is still needed. For a code example check out my last post in issue #1 . Nonetheless: The code required is fairly reduced, and should be much more user friendly.