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/common/runtime.cpp

@@ -571,6 +571,9 @@ StringMap<Type, TYPE_MAX_ENUM>::Entry typeEntries[] =
 	{"ImageData", IMAGE_IMAGE_DATA_ID},
 	{"CompressedData", IMAGE_COMPRESSED_DATA_ID},
 
+	// Joystick
+	{"Joystick", JOYSTICK_JOYSTICK_ID},
+
 	// Math
 	{"RandomGenerator", MATH_RANDOM_GENERATOR_ID},
 	{"BezierCurve", MATH_BEZIER_CURVE_ID},
@@ -582,6 +585,9 @@ StringMap<Type, TYPE_MAX_ENUM>::Entry typeEntries[] =
 	{"SoundData", SOUND_SOUND_DATA_ID},
 	{"Decoder", SOUND_DECODER_ID},
 
+	// Mouse
+	{"Cursor", MOUSE_CURSOR_ID},
+
 	// Physics
 	{"World", PHYSICS_WORLD_ID},
 	{"Contact", PHYSICS_CONTACT_ID},