Refactor FeatureTrack to remove redundant feature finding code

We also tweak the max level finding, because in multi locus view where not all frames have the same levels, we were getting ArrayIndexOutOfBoundsExceptions due to the fact that the level was being found track-wide, instead of just for the specific PackedFeaturesMap
Synchronize packedFeaturesMap

Not sure if this is necessary or helpful

IGV-1944
Fix AbstractDMUtilsTest so the class gets set up properly