Clean up chart update code a bit

Also break out the "Pain" injury category, since D3 clumps them into the
same bar, but they are filtered independently.
Update map on filter change

Still need better filtering of victims, but this gets the process
started.
Remove unused classes and UI elements

The filter dialog and CollisionStatistics type are no longer used. Just
remove them.
Clean up data addition and filter change

Reduce the duplication of logic for appending data and changing the
filter settings.