Rename tilePositions() to sortPositionsIntoTiles()

the first name was confusing.

include/TileGenerator.h

@@ -95,7 +95,7 @@ public:
 	void setZoom(int zoom);
 	void setScales(uint flags);
 	void setDontWriteEmpty(bool f);
-	void tilePositions();
+	void sortPositionsIntoTiles();
 
 private:
 	void parseColorsStream(std::istream &in);