Add: [Script] GetAirportNumHelipads (#12085)

Adds a function for Scripts to get the number of helipads of an airport type.

Remove: [Script] CONFIG_RANDOM from AddSetting flags (#11942)

It had a very weird interaction, and was only ever used by a single
AI.

Fix: Some Script::IsValidVehicle checks need to be complemented with IsPrimaryVehicle

Add: [Script] ScriptVehicle.IsPrimaryVehicle

Change: [Script] A ScriptText with too many parameters is now a fatal error

It should never happen as adding/setting parameters already checks that anyway.

Fix: ScriptRoad::HasRoadType really check for RoadType

Script::HasRoadType was only checking if the tile had the same RoadTramType as that of the RoadType provided.
Now it really checks RoadType against RoadType.

Change: rebrand 1.12.0 to 12.0

One question that keeps popping up: "when do we release 2.0?".
NewGRF will force that at least 1.16 will be 2.0, but to not wait
for this, let's drop the "1." and be for ever done with that
conversation.

We are following in the footstep of giants here.

Add: [Script] Basic information about loaded NewGRFs for scripts. (#9464)

Currently, scripts use various heuristics to detect loaded NewGRFs that are inherently unreliable.
The list of loaded NewGRFs is easily accessible to a human player, and thus giving
scripts the same information is consistent with the current approach to not give scripts
more information than a human player.

Fix 02e770ff: allow estimating CloneVehicle if short on money (#8748)

CheckCompanyHasMoney() was also executed when not using DC_EXEC,
resulting in an error about shortage of money instead of the
estimation.
This mostly is a problem for AI players, as they will have no
way to know how much it would have cost.

Add: [Script] ScriptCargo::GetName, to get the human readable name of a cargo (#8544)

Of course this translates into AICargo.GetName() for AIs and
GSCargo.GetName() for GameScripts.

Add: Allow GameScript to demolish without a company

This allows GameScripts to shrink towns as well as grow them.

Doc: Changed several files to unificate them... (#6964)

...with those from release 1.8 branch.

Add: AI/GS GetMonthlyMaintenanceCost (#6897)

API addition which allows AI/GS scripts to retrieve the monthly maintenance cost of an airport type.

(svn r25213) -Fix [FS#5537]: clarify on which tiles IsDesertTile and IsSnowTile work, i.e. the ones without infrastructure or buildings
-Feature: introduce GetTerrainType which allows one to get that information for tiles with buildings and infrastructure as well