add new gamecontroller APIs

- add mappings after init (or even before w/o using the hint)
- get string for axis
- get string for button
- get mapping string for controller or for GUID
- new event to notify when a controller is remapped. (e.g. mapping was changed via the AddMapping method)

include/SDL_events.h

@@ -100,6 +100,7 @@ typedef enum
 	SDL_CONTROLLERBUTTONUP,            /**< Game controller button released */
 	SDL_CONTROLLERDEVICEADDED,         /**< A new Game controller has been inserted into the system */
 	SDL_CONTROLLERDEVICEREMOVED,       /**< An opened Game controller has been removed */
+	SDL_CONTROLLERDEVICEREMAPPED,      /**< The controller mapping was updated */
 
     /* Touch events */
     SDL_FINGERDOWN      = 0x700,
@@ -358,9 +359,9 @@ typedef struct SDL_ControllerButtonEvent
  */
 typedef struct SDL_ControllerDeviceEvent
 {
-	Uint32 type;        /**< ::SDL_CONTROLLERDEVICEADDED or ::SDL_CONTROLLERDEVICEREMOVED */
+	Uint32 type;        /**< ::SDL_CONTROLLERDEVICEADDED, ::SDL_CONTROLLERDEVICEREMOVED, or ::SDL_CONTROLLERDEVICEREMAPPED */
 	Uint32 timestamp;
-	Uint32 which;       /**< The joystick device index for the ADDED event, instance id for the REMOVED event */
+	Uint32 which;       /**< The joystick device index for the ADDED event, instance id for the REMOVED or REMAPPED event */
 } SDL_ControllerDeviceEvent;
 
 
@@ -484,7 +485,7 @@ typedef union SDL_Event
     SDL_JoyHatEvent jhat;           /**< Joystick hat event data */
     SDL_JoyButtonEvent jbutton;     /**< Joystick button event data */
     SDL_JoyDeviceEvent jdevice;     /**< Joystick device change event data */
-	SDL_ControllerAxisEvent caxis;		/**< Game Controller button event data */
+	SDL_ControllerAxisEvent caxis;		/**< Game Controller axis event data */
 	SDL_ControllerButtonEvent cbutton;  /**< Game Controller button event data */
 	SDL_ControllerDeviceEvent cdevice;  /**< Game Controller device event data */
     SDL_QuitEvent quit;             /**< Quit request event data */

include/SDL_gamecontroller.h

@@ -90,7 +90,7 @@ typedef struct SDL_GameControllerButtonBind
  *		}
  *  }
  *
- *  Using the SDL_HINT_GAMECONTROLLERCONFIG hint you can add support for controllers SDL is unaware of or cause an existing controller to have a different binding. The format is:
+ *  Using the SDL_HINT_GAMECONTROLLERCONFIG hint or the SDL_GameControllerAddMapping you can add support for controllers SDL is unaware of or cause an existing controller to have a different binding. The format is:
  *	guid,name,mappings
  *
  *  Where GUID is the string value from SDL_JoystickGetGUIDString(), name is the human readable string for the device and mappings are controller mappings to joystick ones.
@@ -106,6 +106,26 @@ typedef struct SDL_GameControllerButtonBind
  *
  */
 
+/**
+ *  Add or update an existing mapping configuration
+ *
+ * \return 1 if mapping is added, 0 if updated, -1 on error
+ */
+extern DECLSPEC int SDLCALL SDL_GameControllerAddMapping( const char* mappingSring );
+
+/**
+ *  Get a mapping string for a GUID
+ *
+ *  \return the mapping string.  Must be freed with SDL_free.  Returns NULL if no mapping is available
+ */
+extern DECLSPEC char * SDLCALL SDL_GameControllerMappingForGUID( SDL_JoystickGUID guid );
+
+/**
+ *  Get a mapping string for an open GameController
+ *
+ *  \return the mapping string.  Must be freed with SDL_free.  Returns NULL if no mapping is available
+ */
+extern DECLSPEC char * SDLCALL SDL_GameControllerMapping( SDL_GameController * gamecontroller );
 
 /**
  *  Is the joystick on this index supported by the game controller interface?
@@ -186,6 +206,11 @@ typedef enum
  */
 extern DECLSPEC SDL_GameControllerAxis SDLCALL SDL_GameControllerGetAxisFromString(const char *pchString);
 
+/**
+ *  turn this axis enum into a string mapping
+ */
+extern DECLSPEC const char* SDLCALL SDL_GameControllerGetStringForAxis(SDL_GameControllerAxis axis);
+
 /**
  *  Get the SDL joystick layer binding for this controller button mapping
  */
@@ -233,6 +258,10 @@ typedef enum
  */
 extern DECLSPEC SDL_GameControllerButton SDLCALL SDL_GameControllerGetButtonFromString(const char *pchString);
 
+/**
+ *  turn this button enum into a string mapping
+ */
+extern DECLSPEC const char* SDLCALL SDL_GameControllerGetStringForButton(SDL_GameControllerButton button);
 
 /**
  *  Get the SDL joystick layer binding for this controller button mapping