Added properties to various SDL objects

The following objects now have properties that can be user modified:
* SDL_AudioStream
* SDL_Gamepad
* SDL_Joystick
* SDL_RWops
* SDL_Renderer
* SDL_Sensor
* SDL_Surface
* SDL_Texture
* SDL_Window

include/SDL3/SDL_properties.h

@@ -111,6 +111,21 @@ extern DECLSPEC int SDLCALL SDL_SetProperty(SDL_PropertiesID props, const char *
  */
 extern DECLSPEC void *SDLCALL SDL_GetProperty(SDL_PropertiesID props, const char *name);
 
+/**
+ * Clear a property on a set of properties
+ *
+ * \param props the properties to modify
+ * \param name the name of the property to clear
+ *
+ * \returns 0 on success or a negative error code on failure; call
+ *          SDL_GetError() for more information.
+ *
+ * \since This function is available since SDL 3.0.0.
+ *
+ * \sa SDL_GetProperty
+ */
+extern DECLSPEC int SDLCALL SDL_ClearProperty(SDL_PropertiesID props, const char *name);
+
 /**
  * Destroy a set of properties
  *