Sequence fixes

[stiv-iv]

Fixed these issues in Sequence.lua:

https://github.com/NicMagnier/PlaydateSequence/issues/8 https://github.com/NicMagnier/PlaydateSequence/issues/9 https://github.com/NicMagnier/PlaydateSequence/issues/10 (in Noble engine you can get two calls of scene:finish() in one scene transition)