Added width & height members to Tile, moved local functions to utility.*pp

I've added more members to the Tile structure, namely the width & height
of the tile. This is to fix a circular logic problem, which is too
abstract for this commit message ;)

I've also moved the local/static/inline/etc. utility functions to their
own module in the common directory, because this is just cleaner that
redefining the same code a dozen times.

The map's logic is still the same, but I need to keep moving; I've been
procrastinating far too much.

editor/tile.hpp

@@ -24,11 +24,24 @@
 
 //explicitly a POD
 struct Tile {
+	//position relative to the Region
 	int x, y, depth;
-	int value;
+
+	//graphics
+	int width, height;
+	int sheetIndex, tileIndex;
 
 	Tile() = default;
-	Tile(int i, int j, int k, int l) : x(i), y(j), depth(k), value(l) {}
+	Tile(int _x, int _y, int _depth, int _width, int _height, int _sheetIndex, int _tileIndex) {
+		//The order of the arguments should be explicit
+		x = _x;
+		y = _y;
+		depth = _depth;
+		width = _width;
+		height = _height;
+		sheetIndex = _sheetIndex;
+		tileIndex = _tileIndex;
+	}
 };
 
 bool operator<(Tile const& lhs, Tile const& rhs);