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/types.h

@@ -58,6 +58,9 @@ enum Type
 	IMAGE_IMAGE_DATA_ID,
 	IMAGE_COMPRESSED_DATA_ID,
 
+	// Joystick
+	JOYSTICK_JOYSTICK_ID,
+
 	// Math
 	MATH_RANDOM_GENERATOR_ID,
 	MATH_BEZIER_CURVE_ID,
@@ -69,6 +72,9 @@ enum Type
 	SOUND_SOUND_DATA_ID,
 	SOUND_DECODER_ID,
 
+	// Mouse
+	MOUSE_CURSOR_ID,
+
 	// Physics
 	PHYSICS_WORLD_ID,
 	PHYSICS_CONTACT_ID,
@@ -135,6 +141,9 @@ const bits GRAPHICS_SHADER_T = (bits(1) << GRAPHICS_SHADER_ID) | OBJECT_T;
 const bits IMAGE_IMAGE_DATA_T = (bits(1) << IMAGE_IMAGE_DATA_ID) | DATA_T;
 const bits IMAGE_COMPRESSED_DATA_T = (bits(1) << IMAGE_COMPRESSED_DATA_ID) | DATA_T;
 
+// Joystick.
+const bits JOYSTICK_JOYSTICK_T = (bits(1) << JOYSTICK_JOYSTICK_ID) | OBJECT_T;
+
 // Math.
 const bits MATH_RANDOM_GENERATOR_T = (bits(1) << MATH_RANDOM_GENERATOR_ID) | OBJECT_T;
 const bits MATH_BEZIER_CURVE_T = (bits(1) << MATH_BEZIER_CURVE_ID) | OBJECT_T;
@@ -146,6 +155,9 @@ const bits AUDIO_SOURCE_T = (bits(1) << AUDIO_SOURCE_ID) | OBJECT_T;
 const bits SOUND_SOUND_DATA_T = (bits(1) << SOUND_SOUND_DATA_ID) | DATA_T;
 const bits SOUND_DECODER_T = bits(1) << SOUND_DECODER_ID;
 
+// Mouse.
+const bits MOUSE_CURSOR_T = (bits(1) << MOUSE_CURSOR_ID) | OBJECT_T;
+
 // Physics.
 const bits PHYSICS_WORLD_T = (bits(1) << PHYSICS_WORLD_ID) | OBJECT_T;
 const bits PHYSICS_CONTACT_T = (bits(1) << PHYSICS_CONTACT_ID) | OBJECT_T;