Complete roguelike tutorial using C++ and libtcod - part 7: the GUI

Complete roguelike tutorial using C++ and libtcod ; -originally written by Jice; Text in this tutorial was released under the Creative Commons Attribution-ShareAlike 3.0 Unported and the GNU Free Documentation License (unversioned, with no invariant sections, front-cover texts, or back-cover texts) on 2015-09-21.
	part 1: setting up; part 2: map and actors; part 3: dungeon building; part 4: field of view; part 5: preparing for combat; part 6: going berserk!; part 7: the GUI; part 8: items and inventory; part 9: spells and ranged combat; part 10.1: persistence; part 10.2: game menu; part 11: dungeon levels and character progression; extra 1: about editors and IDE; extra 2: debugging; extra 3: scent tracking; extra 4: makefiles; extra 5: more generic items;

After the longish article 6 about melee fighting, we're going to take a break and do something easier.

First, we're going to slightly improve the player health bar with some visual fluff.
We will also move the game log from the standard output to the game window.
Finally, we will start to use the mouse and implement a mouse look feature to display information about what is under the mouse cursor.

These are three very distinct features but for the sake of simplicity, we will stuff everything in a single Gui class (for Graphical User Interface).

libtcod functions used in this article