Add notice code
This change adds a notice feature to the occlusion code.
The primary feature is to account for the fact that some vehicles (notably, not ego) are driven by humans that need on average, 1.5 seconds to react to a vehicle becoming unoccluded.
For a vehicle to show up in the history for an observer, it must be both visible and noticed at that timestep. This code checks to make sure that a vehicle was visible or noticed 1.5 seconds ago as well as visible for a large enough period within that 1.5 seconds to be registered. It then modifies the observation history for each timestep to make all timesteps within that 1.5-second period retroactively noticed.
Included is also a modification to the visualization system so we can see if a vehicle is visible (green fill), noticed (green outline), or both. (Black otherwise for both)