JointHypothesis Property definition

[dlast-dstl]

JointHypothesis Property "hypotheses" is currently defined as a Hypothesis, when in reality it is dictionary with the form Track:Hypothesis. It is defined this way because then Hypothesis would import Track, and Track imports Update, and Update imports Hypothesis, which is a circular import. This occurs because the function "get_measurement_prediction()" somehow ended up in the Updater rather than the Predictor. When the function is correctly moved back to the Predictor, this issue can be resolved.

[dlast-dstl]

After discussion with the team, keeping "get_measurement_prediction()" in the Updater is sufficiently important that we will just work around this issue.