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_sheet.cpp

@@ -1,22 +1,29 @@
+/* Copyright: (c) Kayne Ruse 2013
+ * 
+ * This software is provided 'as-is', without any express or implied
+ * warranty. In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ * 
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ * 
+ * 1. The origin of this software must not be misrepresented; you must not
+ * claim that you wrote the original software. If you use this software
+ * in a product, an acknowledgment in the product documentation would be
+ * appreciated but is not required.
+ * 
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ * misrepresented as being the original software.
+ * 
+ * 3. This notice may not be removed or altered from any source
+ * distribution.
+*/
 #include "tile_sheet.hpp"
 
-#include <algorithm>
-#include <stdexcept>
+#include "utility.hpp"
 
-static inline std::string truncatePath(std::string pathname) {
-	//TODO: move this into a utilities module?
-	return std::string(
-		std::find_if(
-			pathname.rbegin(),
-			pathname.rend(),
-			[](char ch) -> bool {
-				//windows only
-				return ch == '/' || ch == '\\';
-//				//unix only
-//				return ch == '/';
-			}).base(),
-		pathname.end());
-}
+#include <stdexcept>
 
 SDL_Surface* TileSheet::LoadSurface(std::string fname, Uint16 w, Uint16 h) {
 	//setup the image