[PATCH] Inconsistency in decay and regen rate sharing.

[mimo]

A defenseTower has a decay rate of 5, and a regenRate for each garrisoned unit of 5. So we would naively think that a single unit is enough to stop its decay when captured in enemy territory. That's true if in the middle of the enemy territory, but not if at the border of the enemy territory which looks really inconsistent. The problem comes from the sharing of the cp points between the enemy and gaia when at the border. Let's take a tower surrounded at 60% by the enemy and 40% by gaia. The 5 decay points will be divided proportionnally in 3 attributed to the enemy and 2 to gaia. But the regenRate is equally distributed, that is 2.5 taken from the enemy and 2.5 from gaia. But as gaia was attributed only 2, only 4.5 total regen points can be taken and the decay will continue. But if the tower was fully surrounded by the enemy territory, there would be no such inconsistency and the decay would stop. The attached patch fixes the problem.

[mimo]

In 16864:

improve consistency between decay and regen rates for buildings, fixes #3332