[PATCH] Letting technologies replace other technologies

[sanderd17]

Sometimes, different civs want to have different techs that unlock the same things.

Think about a civ in a mod wanting to have an alternative town phase.

For that, it would be handy if a tech can "provide" a different tech. So unlock the same things. F.e., if a tech has the following line

{
  "replaces": ["phase_town_generic"]
}

then everything that depends on the "phase_town_generic" tech will be unlocked. This includes units, buildings and other techs. But the effects defined in the "phase_town_generic" won't be applied.

[Niek]

Patch that allows technologies to mark other technologies as 'researched' using the example json block

[Niek]

Now with modified technologies

[sanderd17]

The default gameplay works nice. But there are two remaining issues:

• The "back to the future" cheat is broken now. Shouldn't be too hard to fix it.
• The AI can't research the regular town phase anymore (there's no problem with the athen town phase). This is also most likely a simple fix. And this will likely also be the case for the city phase.

The code looks good on first sight (though I should check if the AI actually understands the stat changes correctly, the stat changes in the simulation seem to be correct).

[s0600204]

The proposed change breaks the structree. This patch addresses that particular problem.

[Niek]

Includes the AI and cheat fixes

[sanderd17]

In 16678:

Let technologies replace other technologies, and use this for the town and city phase. Main implementation by niektb, structree fix by s0600204. Fixes #3208