Fix adding new sequencer clip that would extend project duration not appearing on top track
[#3028] Fixing up state and timing bugs when multiple sequences are directly clicked rapidly.
[#3028] Removed some forceful pauses when loading and seeking.
[#3028] Fix to time of adding events so state cannot break it.
prevent sync issues
Merge remote-tracking branch 'matt/t3028' into t3028
Merge remote-tracking branch 'scott/t3028' into t3174
Keeps track of media clips that weren't added specifically into the project timeline