We were never resetting the dead state for repaired SAMs. Rather than
tracking that manually, determine liveness from the number of units left
alive.
For building objectives where the group is not assigned to the TGO until
*mission* generation time we still need manual tracking.
Some SAMs have multiple groups (such as an SA-10 group with its
accompanying SA-15 and SA-19 groups). This shows each group's threat and
detection separately on the map, and also makes it so that an SA-10 with
dead radars will no longer contribute to the threat zone just because
the shilka next to it still has a functioning radar.
https://github.com/Khopa/dcs_liberation/issues/647
Fixes https://github.com/Khopa/dcs_liberation/issues/672
Creates threat zones around airfields and non-trivial air defenses (it's
not worth dodging anything with a threat range under 3nm). These threat
zones can be used to aid mission planning and waypoint placement.
https://github.com/Khopa/dcs_liberation/issues/292
When a base is captured we clear its defenses. Those locations need to
be returned to the preset location pool so they can be used for the new
base defenses.
Like with deleting waypoints, these will degrade the flight plan to the
2.1 behavior.
Ascend/descend points aren't in use any more, so I removed those.
