Leonardo
Event watchers are being executed on the inverse order they are added because they are added to the head of the SDL_event_watchers list.
Since watchers are allowed to change events before they are reported (they shouldn't, imo), this breaks code that rely on watcher execution order (such as distributed event handling).
An easy scenario to see this behaving weird to the user is if you add an event watcher to check mouse coordinates and check them again in your event loop. If you add the watcher after renderer's one (which always happens after you have initialized renderer), you get the same event but different coordinates.
The proposed patch adds the event watcher in the tail of the list, not in the beginning, and correctly fixes this problem.
To enable this, set the environment variable SDL_MOUSE_RELATIVE_MODE_WARP to "1"
When mouse relative mode is disabled, put the cursor back where the application expects it to be, instead of where it was when relative mode was enabled.
