[PATCH] Some foundations have more armor than finished buildings

[elexis]

r18045 removed the Armour component of all economic buildings, which must be a mistake (reading the commit message that increases the armor). It yields 10% armor for every damage type, while foundations have 10% hack and crush and 40% pierce armor. This violates the principle that arrows ought to be incapable of destroying buildings.

With 10% pierce armor, 20 archers can break economic buildings (including the market) easily.

Bug reported by WarBeast.

[fatherbushido]

In 18716:

Restores armour entry in economic structure template wich was mistakenly removed in r18045. Slighty reduces stats compares to a20. Fixes #4195. Reported by Warbeast. Agreed by scythetwirler. Reviewed by elexis.