Merged SDL2 changes from bartbes/love-experiments/SDL2 into default.

- Added love.system module, including clipboard functions.

- Added custom hardware cursors (love.mouse.newCursor, love.mouse.setCursor.)

- Revamped love.joystick:
-- added Joystick objects and moved love.joystick functions which operated on individual joysticks to methods on the Joystick objects.
-- Added love.joystick.getJoystick and love.joystick.getJoystickCount.
-- Added events for when joysticks are connected and disconnected.
-- Added 'Gamepad' methods to Joystick objects: Joystick:isGamepad, Joystick:getGamepadAxis, and Joystick:isGamepadDown. They're a common abstraction for xbox controller-like joystick across operating systems.

- Added monitor choosing support and "fullscreen desktop" mode to love.window.

- Moved unicode text input events to their own callback function (love.textinput), removed the key repeat functions from love.keyboard and made the second argument of love.keypressed a boolean saying whether the keypress was a repeat.

- liblove now works with love.window and love.graphics in OS X

src/modules/system/wrap_System.cpp

@@ -0,0 +1,112 @@
+/**
+ * Copyright (c) 2006-2013 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.
+ **/
+
+// LOVE
+#include "wrap_System.h"
+#include "sdl/System.h"
+
+namespace love
+{
+namespace system
+{
+
+static System *instance = 0;
+
+int w_getOS(lua_State *L)
+{
+	luax_pushstring(L, instance->getOS());
+	return 1;
+}
+
+int w_getProcessorCount(lua_State *L)
+{
+	lua_pushinteger(L, instance->getProcessorCount());
+	return 1;
+}
+
+int w_setClipboardText(lua_State *L)
+{
+	const char *text = luaL_checkstring(L, 1);
+	instance->setClipboardText(text);
+	return 0;
+}
+
+int w_getClipboardText(lua_State *L)
+{
+	luax_pushstring(L, instance->getClipboardText());
+	return 1;
+}
+
+int w_getPowerInfo(lua_State *L)
+{
+	int seconds = -1, percent = -1;
+	const char *str;
+
+	System::PowerState state = instance->getPowerInfo(seconds, percent);
+
+	if (!System::getConstant(state, str))
+		str = "unknown";
+
+	lua_pushstring(L, str);
+
+	if (percent >= 0)
+		lua_pushinteger(L, percent);
+	else
+		lua_pushnil(L);
+
+	if (seconds >= 0)
+		lua_pushinteger(L, seconds);
+	else
+		lua_pushnil(L);
+
+	return 3;
+}
+
+static const luaL_Reg functions[] =
+{
+	{ "getOS", w_getOS },
+	{ "getProcessorCount", w_getProcessorCount },
+	{ "setClipboardText", w_setClipboardText },
+	{ "getClipboardText", w_getClipboardText },
+	{ "getPowerInfo", w_getPowerInfo },
+	{ 0, 0 }
+};
+
+extern "C" int luaopen_love_system(lua_State *L)
+{
+	if (instance == 0)
+	{
+		instance = new love::system::sdl::System();
+	}
+	else
+		instance->retain();
+
+	WrappedModule w;
+	w.module = instance;
+	w.name = "system";
+	w.flags = MODULE_T;
+	w.functions = functions;
+	w.types = 0;
+
+	return luax_register_module(L, w);
+}
+
+} // system
+} // love