CaptureDelay is defined per-trait, and the shortest
delay will be used if multiple traits are enabled.
CapturingCondition and BeingCapturedCondition are
global, and are granted when any capture is in progress.
The capture period is defined from when the unit reaches
the cell next to the target, and either starts to wait
or enter the target through to when the capture succeeds
or fails.
This fixes the various edge cases that occur when multiple
Captures or Capturable traits are defined on an actor and
are toggled using conditions.
The Sabotage threshold field moves from Capturable to
Captures in order to simplify the plumbing. The previous
behaviour ingame can be restored by creating a new
capturable type for each threshold level, each with their
own Captures trait.
