Delete Unexposed Images from Level Strip

[TomDoingArt]

Unexposed / unused / abandoned images linger in the level and it would be nice to have a way to automatically remove them.

Add an option in the Level Strip to delete any images from the level which are not currently exposed on the timeline in the current scene.
NOTE: this will not have awareness of all the places the level may be referenced due to use of the "Load" rather than "Import" option.