Add the ability to have formally deprecated functions.

Functions which are deprecated will print out a message and show up in a small dialog on-screen, when they're first called. Deprecation output is disabled in fused mode by default, and can be modified with love.setDeprecationOutput(enable).

--HG--
branch : minor

src/modules/graphics/Deprecations.h

@@ -0,0 +1,51 @@
+/**
+ * Copyright (c) 2006-2017 LOVE Development Team
+ *
+ * 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.
+ **/
+
+#pragma once
+
+#include "common/Object.h"
+
+namespace love
+{
+namespace graphics
+{
+
+class Graphics;
+class Font;
+
+class Deprecations
+{
+public:
+
+	Deprecations();
+	~Deprecations();
+
+	void draw(Graphics *gfx);
+
+private:
+
+	int currentDeprecationCount;
+	double lastUpdatedTime;
+	StrongRef<Font> font;
+
+}; // Deprecations
+
+} // graphics
+} // love