Ground Attack unrealistic for medium bombers

[Tolwyn]

Create a new attackTimeOut option for the GAttack waypoint.

Set an attackTimeOut (in minutes or seconds or both) for any waypoint that has a target or GAttack waypoint.

For level bombing, don't use it of course, but for A20 and such, they will continue to attack the area until:

percentage is destroyed
or timeout reached

then proceed to next waypoint.