Delete legacy scenarios
Switch sonar categories to "NO_BOW_NULL" from "HAS_BOW_NULL"
Introduce array steady time. Defer for future scenarios
Drop passive king from 2c, save it for 2d
Introduce 2d, where the target starts off in player's bow null.
Introduce 3 more series to the time bearing display, to allow plotting of more targets
Reduce width of time bearing display, to ease development on 1024 monitor.
Oversight - actually need more time series slots
Introduce scenario that has merchant ship
Add unique series names, as well as source id.  Also insert extra side lobes for very noisy targets