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/System.h

@@ -0,0 +1,101 @@
+/**
+ * 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.
+ **/
+
+#ifndef LOVE_SYSTEM_H
+#define LOVE_SYSTEM_H
+
+// LOVE
+#include "common/config.h"
+#include "common/Module.h"
+#include "common/StringMap.h"
+
+// stdlib
+#include <string>
+
+namespace love
+{
+namespace system
+{
+
+class System : public Module
+{
+public:
+
+	enum PowerState
+	{
+		POWER_UNKNOWN,
+		POWER_BATTERY,
+		POWER_NO_BATTERY,
+		POWER_CHARGING,
+		POWER_CHARGED,
+		POWER_MAX_ENUM
+	};
+
+	virtual ~System() {}
+
+	/**
+	 * Gets the current operating system.
+	 **/
+	std::string getOS() const;
+
+	/**
+	 * Gets the number of reported CPU cores on the current system.
+	 * Does not account for technologies such as Hyperthreading: a 4-core
+	 * Hyperthreading-enabled Intel CPU will report 8, instead of 4.
+	 **/
+	virtual int getProcessorCount() const = 0;
+
+	/**
+	 * Replaces the contents of the system's text clipboard with a string.
+	 * @param text The clipboard text to set.
+	 **/
+	virtual void setClipboardText(const std::string &text) const = 0;
+
+	/**
+	 * Gets the contents of the system's text clipboard.
+	 **/
+	virtual std::string getClipboardText() const = 0;
+
+	/**
+	 * Gets information about the system's power supply.
+	 *
+	 * @param[out] seconds Time in seconds of battery life left.
+	 *             -1 if a value can't be determined.
+	 * @param[out] percent The percentage of battery life left (0-100.)
+	 *             -1 if a value can't be determined.
+	 *
+	 * @return The current state of the battery.
+	 **/
+	virtual PowerState getPowerInfo(int &seconds, int &percent) const = 0;
+
+	static bool getConstant(const char *in, PowerState &out);
+	static bool getConstant(PowerState in, const char *&out);
+
+private:
+
+	static StringMap<PowerState, POWER_MAX_ENUM>::Entry powerEntries[];
+	static StringMap<PowerState, POWER_MAX_ENUM> powerStates;
+
+}; // System
+
+} // system
+} // love
+
+#endif // LOVE_SYSTEM_H