[PATCH] Clean up productionQueue in preparation for capturing

[sanderd17]

When capturing a building, you can't disable the productionQueue (it would make capturing useless). You also can't allow people to keep producing the units that were available before (as it would make mercenary-civs lose their uniqueness, and it will be hard to keep track of your army when you have 2 versions of every unit).

So I propose to have a list of trainable units per civ, and in the productionQueue filter those units on Class combos. With the newly possible AND and OR combinations. This should be as versatile as possible.

I did have to add some classes. Like I needed to make a difference between CitizenSoldiers that could be trained from the CC only, or also from the Baracks. Or to make a difference between the Champions available in the barracks (for which you need to research a tech), or those in the fortresses.

I also opted to not replace the current Entities list, but rather extend it. So if you have a special building that should really produce that one specific unit, and not other champions, you can still use the Entities list.

The proposal is about finished for the CC, fortress and barracks. Other unit producing buildings (temple, houses, docks, special buildings ...) are still mostly missing.

Please take a look at it