Breaking Changes
- Update `calloop` to 0.13.0, `calloop-wayland-source` to `0.3.0`.
- Add `surface_enter`/`surface_leave` methods to `CompositorHandler` trait.
- Require explicit unlock call in SessionLock.
- Pass layout to `KeyboardHandler::update_modifiers`.
- Update `wayland-protocols-*`.

Fixed
- Require explicit unlock call in `SessionLock` to avoid accidental unlock.
- Work around touch up events delivered too late with certain Weston versions.
- Internal DnD event handlers are provided position and surface.
- `MultiPool::get` returns an overlap error when its appropriate.
- Fix `delegate_*` macros with custom `UserData`.

Additions
- Method to make subsurface from surface.
- Track latest touch_down event serial.
- Try alternative cursor icon names.
- Implement support for xdg-activation.
- Implement support for session-lock.