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 #10439: [GS] Validate story page button colour, flags, cursor and vehicle type (#11892)

Adds GSStoryPage::IsValidStoryPageButtonColour, GSStoryPage::IsValidStoryPageButtonFlags and GSStoryPage::IsValidStoryPageButtonCursor to the API.

Add missing enforced preconditions to validate parameters passed to MakePushButtonReference, MakeTileButtonReference and MakeVehicleButtonReference.

Fix #10438: [GS] Validate story page element type for ScriptStoryPage::NewElement (#11888)

Fixes a crash that happens if an invalid StoryPageElementType is passed to ScriptStoryPage::NewElement.

Adds an enforced precondition that tests the validity of StoryPageElementType.

Adds GSStoryPage::IsValidStoryPageElementType to the API.

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.

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.

Feature: Push-buttons on storybook pages (#7896)

Allow more direct player-initiated interaction for Game Scripts, by letting the GS put push-buttons on storybook pages. These buttons can either trigger an immediate event, or require the player to first select a tile on the map, or a vehicle.

Additionally this reworks how the storybook pages are layouted and rendered, to allow for slightly more complex layouts, and maybe speeding drawing up a bit.

Feature: GS method to control engine availability for a specific company (#7791)

* Feature: GS method to allow company to use an engine before its introduction date

* Feature: GS method to retire an engine early for a specific company

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