Removed IDList, IDListComparable, and TimelineBuilder which were all not
being used. Also dereferenced serializedVideoFile after using it in
Clip.readObject, though it doesn't appear to affect the amount of memory
I seem to be using.
TimelinePlayer works! Plus I started to implement seek, but it's not how
I want. Going to use a property for current time so that parent objects
can bind to it.